Methods and systems for writing an optical code within or on a fiber substrate

Description

TECHNICAL FIELD

This invention relates to identification elements, and more particularly to method of manufacturing diffraction grating based optical identification elements.

BACKGROUND ART

Many industries have a need for uniquely identifiable objects or for the ability to uniquely identify objects, for sorting, tracking, and/or identification/tagging. Existing technologies, such as bar codes, electronic microchips/transponders, radio-frequency identification (RFID), and fluorescence and other optical techniques, are often inadequate. For example, existing technologies may be too large for certain applications, may not provide enough different codes, or cannot withstand harsh temperature, chemical, nuclear and/or electromagnetic environments.

Therefore, it would be desirable to obtain a coding element or platform that provides the capability of providing many codes (e.g., greater than 1 million codes), that can be made vera small, and/or that can withstand harsh environments.

SUMMARY OF THE INVENTION

Objects of the present invention include a method of manufacturing a plurality of diffraction grating based optical identification elements (microbeads) having unique codes.

According to the present invention, a method of manufacturing optical identification elements comprises forming a diffraction grating in a fiber substrate along a longitudinal axis of said substrate, said grating having a resultant refractive index variation, and cutting the substrate transversely to form a plurality of optical identification elements, said elements having said grating therein along substantially the entire length of said elements and each of said elements have substantially the same resultant refractive index variation.

The foregoing and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of exemplary embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an optical identification element, in accordance with the present invention.

FIG. 2 is a top level optical schematic for reading a code in an optical identification element, in accordance with the present invention.

FIG. 3 is a block diagram of the steps of manufacturing a diffraction grating-based optical identification element or microbead, in accordance with the present invention.

FIG. 4 is an elevational view of a fiber stripping station, in accordance with the present invention.

FIG. 5 is a perspective view of a cage having a pair of fiber ribbons wound thereabout, in accordance with the present invention.

FIG. 6 is a side view of a cage having a fiber ribbon wound thereabout, in accordance with the present invention.

FIG. 7 is a perspective view of a disk having a fiber ribbon wound thereabout, in accordance with the present invention.

FIG. 8 is a top view of a grating writing station, in accordance with the present invention.

FIG. 9 is a top view of another embodiment of a grating writing station, in accordance with the present invention.

FIG. 10 is a front view of a section of a fiber ribbon and a projection of a UV beam from a laser for writing a grating that is narrower than the width of the fiber ribbon, in accordance with the present invention.

FIG. 11 is a front view of a section of a fiber ribbon and a projection of a UV beam from a laser for writing a grating that is wider than the width of the fiber ribbon, in accordance with the present invention.

FIG. 12 is a front view of a section of a fiber ribbon and a projection of a UV beam from a laser and a phase mask tilted at a blaze angle, in accordance with the present invention.

FIG. 13 is a perspective view of a plurality of fiber ribbons adhered to a test fixture, in accordance with the present invention.

FIG. 14 is a side view of a plurality of fiber ribbons adhered to a test fixture, in accordance with the present invention.

FIG. 15 is an expanded top view of a portion of the diced fiber ribbon, in accordance with the present invention.

FIG. 16 is a side view of separation station having a section of fiber ribbon disposed in a vessel, in accordance with the present invention.

FIG. 17 is a side view of the vessel of FIG. 16 having a vial disposed on one end of the vessel, in accordance with the present invention.

FIG. 18 is a side view of the vessel and vial of FIG. 16 in a turned over orientation, in accordance with the present invention.

FIG. 19 is a side view of microbeads disposed within a vial, in accordance with the present invention.

FIG. 20 is a top view of another embodiment of a grating writing station, in accordance with the present invention.

FIG. 21 is a perspective of another embodiment of a grating writing station, in accordance with the present invention.

FIG. 22 is a side view of a pair of lasers scoring opposing sides of a fiber to form microbeads, in accordance with the present invention.

FIG. 23 is a side view of a laser scoring one side of a fiber to form microbeads, in accordance with the present invention.

FIG. 24 is a side view of an anvil and support used to separate the microbeads from the scored fiber, in accordance with the present invention.

FIG. 25 is a schematic illustration of another method of manufacturing microbeads, in accordance with the present invention.

FIG. 26 is a side view of another embodiment for cutting a fiber to form microbeads, in accordance with the present invention.

FIG. 27 is an optical schematic for reading a code in an optical identification element, in accordance with the present invention.

FIG. 28 is an image of a code on a CCD camera from an optical identification element, in accordance with the present invention.

FIG. 29 is a graph showing an digital representation of bits in a code in an optical identification element, in accordance with the present invention.

FIG. 30 illustrations (a)-(c) shown images of digital codes on a CCD camera, in accordance with the present invention.

FIG. 31 illustrations (a)-(d) show graphs of different refractive index pitches and a summation graph, in accordance with the present invention.

FIG. 32 is an alternative optical schematic for reading a code in an optical identification element, in accordance with the present invention.

FIG. 33 illustrations (a)-(b) are graphs of reflection and transmission wavelength spectrum for an optical identification element, in accordance with the present invention.

FIGS. 34-35 are side views of a thin grating for an optical identification element, in accordance with the present invention.

FIG. 36 is a perspective view showing azimuthal multiplexing of a thin grating for an optical identification element, in accordance with the present invention.

FIG. 37 is side view of a blazed grating for an optical identification element, in accordance with the present invention.

FIG. 38 is a graph of a plurality of states for each bit in a code for an optical identification element, in accordance with the present invention.

FIG. 39 is a side view of an optical identification element where light is incident on an end face, in accordance with the present invention.

FIGS. 40-41 are side views of an optical identification element where light is incident on an end face, in accordance with the present invention.

FIG. 42, illustrations (a)-(c) are side views of an optical identification element having a blazed grating, in accordance with the present invention.

FIG. 43 is a side view of an optical identification element having a coating, in accordance with the present invention.

FIG. 44 is a side view of whole and partitioned optical identification element, in accordance with the present invention.

FIG. 45 is a side view of an optical identification element having a grating across an entire dimension, in accordance with the present invention.

FIG. 46, illustrations (a)-(c), are perspective views of alternative embodiments for an optical identification element, in accordance with the present invention.

FIG. 47, illustrations (a)-(b), are perspective views of an optical identification element having multiple grating locations, in accordance with the present invention.

FIG. 48, is a perspective view of an alternative embodiment for an optical identification element, in accordance with the present invention.

FIG. 49 is a view an optical identification element having a plurality of gratings located rotationally around the optical identification element, in accordance with the present invention.

FIG. 50 illustrations (a)-(e) show various geometries of an optical identification element that may have holes therein, in accordance with the present invention.

FIG. 51 illustrations (a)-(c) show various geometries of an optical identification element that may have teeth thereon, in accordance with the present invention.

FIG. 52 illustrations (a)-(c) show various geometries of an optical identification element, in accordance with the present invention.

FIG. 53 is a side view an optical identification element having a reflective coating thereon, in accordance with the present invention.

FIG. 54 illustrations (a)-(b) are side views of an optical identification element polarized along an electric or magnetic field, in accordance with the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 1, a diffraction grating-based optical identification element 8 (or encoded element or coded element) comprises a known optical substrate 10, having an optical diffraction grating 12 disposed (or written, impressed, embedded, imprinted, etched, grown, deposited or otherwise formed) in the volume of or on a surface of a substrate 10. The grating 12 is a periodic or aperiodic variation in the effective refractive index and/or effective optical absorption of at least a portion of the substrate 10.

The optical identification element 8 described herein is the same as that described in Copending patent application Ser. No. 10/661,234, filed contemporaneously with the parent application, which is incorporated herein by reference in its entirety.

In particular, the substrate 10 has an inner region 20 where the grating 12 is located. The inner region 20 may be photosensitive to allow the writing or impressing of the grating 12. The substrate 10 has an outer region 18, which does not have the grating 12 therein.

The grating 12 is a combination of one or more individual spatial periodic sinusoidal variations (or components) in the refractive index that are collocated at substantially the same location on the substrate 10 along the length of the grating region 20, each having a spatial period (or pitch) Λ. The resultant combination of these individual pitches is the grating 12, comprising spatial periods (Λ1-Λn) each representing a bit in the code. Thus, the grating 12 represents a unique optically readable code, made up of bits, where a bit corresponds to a unique pitch Λ within the grating 12. Accordingly, for a digital binary (0-1) code, the code is determined by which spatial periods (Λ1-Λn) exist (or do not exist) in a given composite grating 12. The code or bits may also be determined by additional parameters (or additional degrees of multiplexing), and other numerical bases for the code may be used, as discussed herein and/or in the aforementioned patent application.

The grating 12 may also be referred to herein as a composite or collocated grating. Also, the grating 12 may be referred to as a “hologram”, as the grating 12 transforms, translates, or filters an input optical signal to a predetermined desired optical output pattern or signal.

The substrate 10 has an outer diameter D1 and comprises silica glass (SiO₂) having the appropriate chemical composition to allows the grating 12 to be disposed therein or thereon. Other materials for the optical substrate 10 may be used if desired. For example, the substrate 10 may be made of any glass, e.g., silica, phosphate glass, borosilicate glass, or other glasses, or made of glass and plastic, or solely plastic. For high temperature or harsh chemical applications, the optical substrate 10 made of a glass material is desirable. If a flexible substrate is needed, plastic, rubber or polymer-based substrate may be used. The optical substrate 10 may be any material capable of having the grating 12 disposed in the grating region 20 and that allows light to pass through it to allows the code to be optically read.

The optical substrate 10 with the grating 12 has a length L and an outer diameter D1, and the inner region 20 diameter D. The length L can range from very small “microbeads” (or microelements, micro-particles, or encoded particles), about 1-1000 microns or smaller, to larger “macrobeads” or “macroelements” for larger applications (about 1.0-1000 mm or greater). In addition, the outer dimension D1 can range from small (less than 1000 microns) to large (1.0-1000 mm and greater). Other dimensions and lengths for the substrate 10 and the grating 12 may be used.

The grating 12 may have a length Lg of about the length L of the substrate 10. Alternatively the length Lg of the grating 12 may be shorter than the total length L of the substrate 10.

The outer region 18 is made of pure silica (SiO₂) and has a refractive index n2 of about 1.458 (at a wavelength of about 1553 nm), and the inner grating region 20 of the substrate 10 has dopants, such as germanium and/or boron, to provide a refractive index n1 of about 1.453, which is less than that of outer region 18 by about 0.005. Other indices of refraction n1,n2 for the grating region 20 and the outer region 18, respectively, may be used, if desired, provided the grating 12 can be impressed in the desired grating region 20. For example, the grating region 20 may have an index of refraction that is larger than that of the outer region 18 or grating region 20 may have the same index of refraction as the outer region 18 if desired.

Referring to FIG. 2, an incident light 24 of a wavelength λ, e.g., 532 nm from a known frequency doubled Nd:YAG laser or 632 nm from a known Helium-Neon laser, is incident on the grating 12 in the substrate 10. Any other input wavelength λ can be used if desired provided λ is within the optical transmission range of the substrate (discussed more herein and/or in the aforementioned patent application). A portion of the input light 24 passes straight through the grating 12, as indicated by a line 25. The remainder of the input light 24 is reflected by the grating 12, as indicated by a line 27 and provided to a detector 29. The output light 27 may be a plurality of beams, each having the same wavelength λ as the input wavelength λ and each having a different output angle indicative of the pitches (Λ1-Λn) existing in the grating 12. Alternatively, the input light 24 may be a plurality of wavelengths and the output light 27 may have a plurality of wavelengths indicative of the pitches (Λ1-Λn) existing in the grating 12. Alternatively, the output light may be a combination of wavelengths and output angles. The above techniques are discussed in more detail herein and/or in the aforementioned patent application.

The detector 29 has the necessary optics, electronics, software and/or firmware to perform the functions described herein. In particular, the detector reads the optical signal 27 diffracted or reflected from the grating 12 and determines the code based on the pitches present or the optical pattern, as discussed more herein or in the aforementioned patent application. An output signal indicative of the code is provided on a line 31.

FIG. 3 shows a method 800 of manufacturing a microbead 8 similar to that described hereinbefore in accordance with the present invention. The first step 802 includes providing a photosensitive substrate or fiber 830. To simplify the description of the method of manufacturing, the substrate will be referred to as a fiber with the understanding that the microbeads 8 may be formed of any photosensitive substrate.

The fiber 830 may be made of any material that has sufficient photosensitivity to allows a diffraction grating 12 to be disposed therein, that represents a code that can be interrogated as described herein and/or in the aforementioned patent application. The fiber 830 may be doped or loaded with any dopant now known or later discovered that allows the fiber to exhibit the necessary level of photosensitivity for the incident radiation (e.g., UV or other actinic radiation) used for writing the grating 12, such as, hydrogen, deuterium, boron, germanium, lead, or other dopants that provide photosensitivity, some of which are described in Patent Nos.: U.S. Pat. No. 6,436,857 to Brueck et al, U.S. Pat. No. 5,287,427 to Atkins et al, U.S. Pat. No. 5,235,659 to Atkins et al, U.S. Pat. No. 6,327,406 to Cullen et al, WO 00/44683 to Samsung Electronics Co. LTD, U.S. Pat. No. 6,221,566 to Kohnke et al, U.S. Pat. No. 6,097,512 to Ainslie et al; and U.S. Pat. No. 6,075,625 to Ainslie et al.

In step 804, the photosensitive fiber 830 is then stripped of the coating or buffer disposed on its outer surface and then cleaned. In step 806, the stripped fiber is then wound around a cage or basket 832 having a generally polygon shape so that the wound fiber has sections 831 of flat areas.

FIG. 4 illustrates a fixture/set-up 834 for accomplishing steps 802-804. The photosensitive fiber 830 is threaded through a blade 836 for stripping the buffer from the fiber. A heater 838 is disposed prior to the stripper 836 to heat and soften the buffer to ease the removal of the buffer from the fiber. The stripped fiber then passes through or between a pair of pads 840 soaked with a solvent, such as acetone, to clean the fiber. The fiber 830 is then wound about the cage 832. While not shown, the set-up 834 may include one or more pulleys or rollers to provide tension on the fiber when winding the fiber onto the cage.

As best shown in FIGS. 5 and 6, the cage 832 has a lower plate 842 and an upper ring support 844 with a plurality of rods 846 connected therebetween. The rods are equi-spaced about the circumference of the cage. In the embodiment shown, the cage 832 includes 16 openings 848, however, the invention contemplates having any number of openings. When wound around the rods 846 of the cage 832, each wrap of fiber is adjacent to and touches each adjacent wrap to form a single layer of fiber ribbon 850 around the cage. The fiber is wrapped around the cage between 100-120 times to effectively form a single layer ribbon of fibers. The invention contemplates any number of wraps of fiber around the cage. The fiber ribbon 850 forms a polygonal shape when wrapped around the cage 832 to provide a plurality of flat sections (16 sections) 831. These flat sections 831 of the fiber ribbon 850 provides the area of the fiber that a grating 12 is written in, which will be described in greater detail hereafter. As best shown in FIG. 6, one section 831 of the fiber ribbon 850 is tape together at 852, including the ends of the fiber, to maintain the tension of the fiber around the cage and to maintain the single layer of the fiber ribbon.

While FIG. 6 shows a single fiber ribbon 850 disposed on the cage 832, the present invention contemplates that a plurality of fiber ribbons 850 may be axially spaced on the cage, as shown in FIG. 5.

FIG. 7 illustrates that the stripped fiber 830 may by wound around a disk 854 having a plurality of circumferentially spaced dovetailed slots 856, wherein the fiber ribbon 850 is taped at 858 to the outer circumference of the disk.

The next step 808 of FIG. 3 is to write or shoot the diffraction grating(s) 12 into each section 831 (see FIGS. 8 and 9) of the fiber ribbon 850. The grating 12 may be impressed in the fiber 830 by any technique for writing, impressed, embedded, imprinted, or otherwise forming a diffraction grating in the volume of or on a surface of a substrate 10. Examples of some known techniques are described in U.S. Pat. Nos. 4,725,110 and 4,807,950, entitled “Method for Impressing Gratings Within Fiber Optics”, to Glenn et al; and U.S. Pat. No. 5,388,173, entitled “Method and Apparatus for Forming Aperiodic Gratings in Optical Fibers”, to Glenn, respectively, and U.S. Pat. No. 5,367,588, entitled “Method of Fabricating Bragg Gratings Using a Silica Glass Phase Grating Mask and Mask Used by Same”, to Hill, and U.S. Pat. No. 3,916,182, entitled “Periodic Dielectric Waveguide Filter”, Dabby et al, and U.S. Pat. No. 3,891,302, entitled “Method of Filtering Modes in Optical Waveguides”, to Dabby et al, which are all incorporated herein by reference to the extent necessary to understand the present invention.

Alternatively, instead of the grating 12 being impressed within the fiber material, the grating 12 may be partially or totally created by etching or otherwise altering the outer surface geometry of the substrate to create a corrugated or carving surface geometry of the substrate, such as is described in U.S. Pat. No. 3,891,302, entitled “Method of Filtering Modes in Optical Waveguides”, to Dabby et al, which is incorporated herein by reference to the extent necessary to understand the present inventions provided the resultant optical refractive profile for the desired code is created.

Further, alternatively, the grating 12 may be made by depositing dielectric layers onto the substrate, similar to the way a known thin film filter is created, so as to create the desired resultant optical refractive profile for the desired code.

FIG. 8 shows the method of writing a grating 12 into the fibers 830 of the ribbon 850 using at least one phase mask 860. A laser 862, such as an excimer laser or CO₂laser, provides an ultra-violet (UV) beam 864, which passes through the phase mask to write a grating 12 having a predetermined profile corresponding to the phase mask. In one embodiment, one phase mask 860 may be used to write the grating into the fiber 830 to provide one unique code for the microbead 8. Each unique phase mask therefore represents one unique code, thereby requiring a phase mask for each code used. Using only one phase mask to generate each code becomes very expensive and difficult to manufacture when the number of unique codes needed increases.

In another embodiment each unique code may be generated by writing a plurality of co-located grating 12 into each section 831 of the fiber ribbon 850. For example, the resulting grating in a particular section 831 (or microbead 8) may comprise any combination of eight (8) gratings using eight (8) different phase masks 860. Consequently the number of unique gratings or codes using eight phase masks equal 2⁸. The phase mask may be mounted to a carriage 866, similar to that shown in FIGS. 20 and 21, that translates parallel to the fiber ribbon 850 to select the mask 860 for writing the desired grating 12. The invention further contemplates that the phase masks are mounted on a wheel (not shown) that can be rotated to select the desired phase mask.

Each of the 16 sections 831 of the fiber ribbon 850 may be written with the same grating 12. Alternatively, each section may have a different grating written therein, each section therefore having a different code associated therewith. To provide different gratings 12 for each section 831 using the co-located grating method, each section would use a different combination of phase masks to write each grating. For example, the first, third and fifth phase masks of the 8 phase masks may be used to write the grating that comprises the three co-located gratings written into the first section 831 of the fiber ribbon 850. For the second section 831 of the fiber ribbon, the first, fifth, sixth and eight phase masks may be used to write the grating that comprises the four co-located gratings written into the second section. The other sections of the fiber ribbon may be similarly written using different combinations of phase masks. While the embodiment shows two grating writing stations 868, it is contemplated the only one station may be used or any number of stations.

FIG. 9 shows another method of writing the gratings 12 into each section 831 of the fiber ribbons 850 by using interfering beams 870 provided by a laser 862. As shown the UV beam 864 is split by a mirror 872 and reflected to a pair of complementary mirrors 874. The complementary mirrors 874 reflect the UV beams 870 back to interfere with each other at the fiber ribbon 850 to form the grating 12. Similar to that described hereinbefore, a single grating may be written in the sections 831 of the fiber ribbon or a plurality of co-located gratings may be written. To change the grating profile or interference pattern to create a different grating 12, the complementary mirrors 874 may be tilted to a different angle.

FIG. 10 illustrates a scanning method for exposing each section 831 of the fiber ribbon 850 using a phase mask 860. In this method, the width of the UV beam 864 used to write the grating 12 is smaller than the width of the fiber ribbon 850. The UV beam 864 translates along the width of the fiber ribbon to scan each of the wraps of fiber 830 in the section of fiber ribbon. In this instance, the beam scan direction 876 is from bottom to top, however, the direction of scan may be from top to bottom of the section. The UV beam 864 may be scanned upward by translating the laser 862, or alternatively, the cage 832 may translated upward and downward in the axial direction.

Alternatively, FIG. 11 illustrates a stationary or blanket method for exposing each section 831 of the fiber ribbon 850 using a phase mask 860. In this method, the width of the UV beam 864 used to write the grating 12 is as wide as or wider than the width of the fiber ribbon 850. This method enables the entire section 831 to be exposed and a grating written in a single exposure.

It is important that the phase mask 860 is square, and not angle, to the section 831 of the fiber ribbon 850 to minimize the blaze angle 878 of the grating 12 as illustrated in FIG. 12. If the blaze angle 878 is too large (e.g., >0.1 degree), the microbeads 8 may not exhibit a code to the reader, as the Bragg condition no longer falls with the Bragg envelope.

In step 810 of FIG. 3, after the gratings 12 are written into each section 831 of the fiber ribbon 850 (except the taped section), a strip of tape 880 (e.g., Kapton tape) is adhered to the outer surface of the fiber ribbon 850 as best shown in FIG. 14. In step 812 of FIG. 3, once taped, the fiber ribbon is cut off the cage 832 by cutting through the taped section 852 of the fiber ribbon 850 at 882 as shown in FIG. 6.

In step 814, the fiber ribbon 850 is flattened and mounted to a thermally conductive fixture 884, as shown in FIGS. 13 and 14. As best shown in FIG. 14, each ribbon 850 is bonded to a plastic sheet material 886 (e.g., polyimide sheet material) that is bonded to the fixture. The adhesive 888 used to bond the polyimide sheet 886 to the fixture 884 and the fiber ribbon 850 to the polyimide sheet is a water-soluble thermoset adhesive, such as that known as Aquabond®. In FIG. 13, the fiber ribbons are secured to the fixture by a pair of clamps 890. The length of the fiber ribbons is approximately 632 mm. Once the fiber ribbons are clamped to the fixture 884, the fixture is heated to liquefy the adhesive 888, which then encases the fibers 830 in the adhesive. The adhesive 888 is allowed to cool and harden to thereby encase the fibers and bond to the polyimide sheet 886 and bond the polyimide sheet to the fixture.

In step 816 of FIG. 3, the kapton tape 880 is then removed from the fiber ribbons 850. In step 818, each section 831 having a grating 12 is cut or diced to form the microbeads 8, as shown in FIG. 15. The intermediate sections 892 having no gratings (see FIG. 13) are not dice and left long. The blades cut sufficiently deep to cut the fibers 830 and score the polyimide sheet 886 without cutting fully through the sheet. FIG. 15 shows a portion of the fiber ribbon 850 and the kerfs 894 created by the cutting blade. Before removing the fiber ribbons from the fixture 884, the intermediate sections 892 are removed from the polyimide sheet 886. One method is to cut that portion away with a blade having a wide kerf. Alternatively, the fixture can be heated to soften the adhesive 888 to permit the intermediate sections 892 of the ribbon 850 to be scraped away. Once the intermediate sections 892 are removed from the fiber ribbons 850, the fiber ribbons are removed from the fixture 884 by heating the fixture to soften the adhesive between the polyimide sheet and the fixture.

In step 820 of FIG. 3, the microbeads 8 are removed from each of section 831 of the fiber ribbon 850. The polyimide sheet 886 is cut across each of the intermediate sections to separate each of the sections 831 having a group of microbeads 8. As shown in FIG. 16, one or more sections 831 having the same code are place within a vessel 896 having a tapered open end 898 and another end having a removable filter 900 (40 um filter material). The section 850 having microbeads 8 is placed into the vessel 896 by removing the filter 900 and replacing it. The vessel is placed filter end down within a vat 902 having water and solvent (e.g., Aquaclean®) solution 904 heated to approximately 86 degrees Celsius. The vat 902 is then placed within an ultrasonic bath 906 of pure water 908, which vibrates the water at approximately 80 KHz. The solution 902 passes through the filter 900 of the vessel 896 and dissolves the water soluble adhesive 888 holding the microbeads 8 to the polyimide sheet 886. The ultrasonic vibration assists with separating the microbeads from the polyimide sheet.

In step 822 of FIG. 3, the microbeads 8 are cleaned and stored. As shown in FIGS. 17 and 18, the vessel 896 is then removed from the vat 902 and a polyethylene vial 910 is placed over the tapered opening 898 of the vessel 896, as shown in FIGS. 17-18. The vessel and vile are then turned upside down and flushed with de-ionized water to clean the microbeads 8. Consequently, the microbeads 8 flows from the vessel 896 to the vial 910. The de-ionized water passes through a dense filter 912 disposed on the bottom of the vial. The polyimide sheet 886 is retained within the vessel 896 because the tapered opening 898 of the vessel is smaller than the sheet. Referring to FIG. 19, another filter 914 is place in the vial 910 to secure the microbeads therein for storage.

FIGS. 20 and 21 illustrate a method of writing at least one grating 12 in a section 831 of a fiber ribbon 850. In this embodiment the fiber ribbon, similar to that described hereinbefore, is wound around a spool 916. The fiber ribbon is drawn through a grating writing station 868 to a take up spool 918. The grating writing station 868 includes a carriage 866 having a plurality of phase masks 860 that linearly translates parallel to the flat section 831 of the fiber ribbon 850. The carriage translates to position the desired phase mask in position to write the proper grating 12. As the fiber ribbon is fed to the grating writing station 868, a set of rollers 920 separate the tape 880 from the fibers 830 and directs the tape away from the ultraviolet (UV) beam 864 to thereby protect the tape from the UV beam. The rollers direct the tape and fibers back together and a pair pinch rollers 922 adhere the fibers 830 back onto the tape 880 to form the fiber ribbon 850. In the operation of the writing station 868, each section 831 of ribbon 850 is sequentially positioned in the writing station. When a section of ribbon is positioned in the writing station, the carriage 866 translates to position a desired phase mask 860 between the laser 862 and the fibers 830. The laser then provides the UV beam to write the grating 12 in the fibers 830. The carriage 866 then translates to position another phase mask to write a second grating onto the section 831 of fibers 830. This operation continues until all the desired gratings are written. The second spool 918 then draws the next section of fibers 830 into the writing station to write the desired grating(s) into the fibers. The grating(s) written into each section of fibers may be the same or different.

Referring to FIGS. 22 and 23, the present invention contemplates cutting/dicing the fibers 830 using a laser 924 (e.g., CO₂laser or excimer laser). In one embodiment the laser 924 may be used to completely cut through the fibers 830. Alternatively, the laser can be used to score the fibers as shown in FIGS. 22 and 23. In FIG. 22, two lasers 924 are used to score both sides of the fibers 830 at the same location, while in FIG. 23, one laser 924 is used to score only one side of the fibers. Once scored, the fibers 830 may be separated to form the microbeads 8 by placing the scored fibers 830 in an ultrasonic bath (at 49 KHz) to vibrate the microbeads 8 apart. Alternatively, as shown in FIG. 24 the microbeads 8 may be separated using a mechanical anvil 928 that snaps or breaks each microbead 8 from the scored fiber 830.

FIG. 25 is a schematic illustration of an alternative method of manufacturing the microbeads 8. As shown, the photosensitive fiber 830 is first stripped and cleaned 930. The gratings 12 are then written into the fiber 932 and then wound 934 onto a second a spool 936. The fiber 830 is then cut off 938 the spool 936 in a plurality of strips 940 of fiber that are flattened out. The strips of fibers are then cut or diced with a blade 942.

If the microbeads 8 should be used to perform a chemical experiment or assay similar to that described in U.S. patent application Ser. No. 10/661,031 and U.S. patent application Ser. No. 10/661,115, both filed contemporaneously, which are incorporated herein by reference, the probe compound or chemical may be coated or applied to the fiber or microbeads at any step in the process of manufacture of the microbeads described hereinbefore.

FIG. 26 illustrates another method of cutting dicing the fibers 830 to form the microbeads 8. As shown, after the grating(s) 12 have been written into the fiber (and in this particle instance, coated/tagged with a probe compound (e.g., Oligo), the fiber 830 is fed into a tubular fiber holder 944. As the fiber is pushed through the holder 944, a cutting device 946 having a blade 948 cuts or scores the fiber 830 to the appropriate length, which is then separates the microbead from the fiber by a torque element 950.

Referring to FIG. 27, the reflected light 27, comprises a plurality of beams 26-36 that pass through a lens 37, which provides focused light beams 46-56, respectively, which are imaged onto a CCD camera 60. The lens 37 and the camera 60, and any other necessary electronics or optics for performing the functions described herein, make up the reader 29. Instead of or in addition to the lens 37, other imaging optics may be used to provide the desired characteristics of the optical image/signal onto the camera 60 (e.g., spots, lines, circles, ovals, etc.), depending on the shape of the substrate 10 and input optical signals. Also, instead of a CCD camera other devices may be used to read/capture the output light.

Referring to FIG. 28, the image on the CCD camera 60 is a series of illuminated stripes indicating ones and zeros of a digital pattern or code of the grating 12 in the element 8. Referring to FIG. 29, lines 68 on a graph 70 are indicative of a digitized version of the image of FIG. 28 as indicated in spatial periods (Λ1-Λn).

Each of the individual spatial periods (Λ1-Λn) in the grating 12 is slightly different, thus producing an array of N unique diffraction conditions (or diffraction angles) discussed more hereinafter. When the element 8 is illuminated from the side, in the region of the grating 12, at an appropriate input angle, e.g., about 30 degrees, with a single input wavelength λ (monochromatic) source, the diffracted (or reflected) beams 26-36 are generated. Other input angles θi may be used if desired, depending on various design parameters as discussed herein and/or in the aforementioned patent application, and provided that a known diffraction equation (Eq. 1 below) is satisfied:

sin(θ_i)+sin(θ_o)=mλ/nΛ Eq. 1

where Eq. 1 is diffraction (or reflection or scatter) relationship between input wavelength λ, input incident angle θi, output incident angle θo, and the spatial period Λ of the grating 12. Further, m is the “order” of the reflection being observed, and n is the refractive index of the substrate 10. The value of m=1 or first order reflection is acceptable for illustrative purposes. Eq. 1 applies to light incident on outer surfaces of the substrate 10 which are parallel to the longitudinal axis of the grating (or the k_Bvector). Because the angles θi,θo are defined outside the substrate 10 and because the effective refractive index of the substrate 10 is substantially a common value, the value of n in Eq. 1 cancels out of this equation.

Thus, for a given input wavelength λ, grating spacing Λ, and incident angle of the input light θi, the angle θo of the reflected output light may be determined. Solving Eq. 1 for θo and plugging in m=1, gives:

θo=sin⁻¹(λ/Λ−sin(θi)) Eq. 2

For example, for an input wavelength λ=532 nm, a grating spacing Λ=0.532 microns (or 532 nm), and an input angle of incidence θi=30 degrees, the output angle of reflection will be θo=30 degrees. Alternatively, for an input wavelength λ=632 nm, a grating spacing Λ=0.532 microns (or 532 nm), and an input angle θi of 30 degrees, the output angle of reflection θo will be at 43.47 degrees, or for an input angle θi=37 degrees, the output angle of reflection will be θo=37 degrees. Any input angle that satisfies the design requirements discussed herein and/or in the aforementioned patent application may be used.

In addition, to have sufficient optical output power and signal to noise ratio, the output light 27 should fall within an acceptable portion of the Bragg envelope (or normalized reflection efficiency envelope) curve 200, as indicated by points 204,206, also defined as a Bragg envelope angle θB, as also discussed herein and/or in the aforementioned patent application. The curve 200 may be defined as:

$\begin{matrix} I (ki, ko) \approx {[KD]}^{2} \sin c^{2} [\frac{(ki - ko) D}{2}] & Eq . 3 \end{matrix}$

where K=2πδn/λ, where, δn is the local refractive index modulation amplitude of the grating and λ is the input wavelength, sin c(x)=sin(x)/x, and the vectors k_i=2π cos(θ_i)/λ and k_o=2π cos(θ_o)/λ are the projections of the incident light and the output (or reflected) light, respectively, onto the line 203 normal to the axial direction of the grating 12 (or the grating vector k_B), D is the thickness or depth of the grating 12 as measured along the line 203 (normal to the axial direction of the grating 12). Other substrate shapes than a cylinder may be used and will exhibit a similar peaked characteristic of the Bragg envelope. We have found that a value for δn of about 10⁻⁴in the grating region of the substrate is acceptable; however, other values may be used if desired.

Rewriting Eq. 3 gives the reflection efficiency profile of the Bragg envelope as:

$\begin{matrix} I (ki, ko) \approx {{[\frac{2 π \cdot δ n \cdot D}{λ}]}^{2} [\frac{Sin (x)}{x}]}^{2} & Eq . 4 \end{matrix}$

where:

x=(ki−ko)D/2=(πD/λ)*(cos θi−cos θo

Thus, when the input angle θi is equal to the output (or reflected) angle θ_o(i.e., θi=θ_o), the reflection efficiency I (Eqs. 3 & 4) is maximized which is at the center or peak of the Bragg envelope. When θi=θo, the input light angle is referred to as the Bragg angle as is known. The efficiency decreases for other input and output angles (i.e., θi≠θ_o), as defined by Eqs. 3 & 4. Thus, for maximum reflection efficiency and thus output light power, for a given grating pitch Λ and input wavelength, the angle θi of the input light 24 should be set so that the angle θo of the reflected output light equals the input angle θi.

Also, as the thickness or diameter D of the grating decreases, the width of the sin(x)/x function (and thus the width of the Bragg envelope) increases and, the coefficient to or amplitude of the sin c²(or (sin(x)/x)²function (and thus the efficiency level across the Bragg envelope) also increases, and vice versa. Further, as the wavelength λ increases, the half-width of the Bragg envelope as well as the efficiency level across the Bragg envelope both decrease. Thus, there is a trade-off between the brightness of an individual bit and the number of bits available under the Bragg envelope. Ideally, δn should be made as large as possible to maximize the brightness, which allows D to be made smaller.

From Eq. 3 and 4, the half-angle of the Bragg envelope θ_Bis defined as:

$\begin{matrix} θ_{B} = \frac{η λ}{π D \sin (θ_{i})} & Eq . 5 \end{matrix}$

where η is a reflection efficiency factor which is the value for x in the sin c²(x) function where the value of sin c²(x) has decreased to a predetermined value from the maximum amplitude as indicated by points 204,206 on the curve 200.

We have found that the reflection efficiency is acceptable when η≦1.39. This value for η corresponds to when the amplitude of the reflected beam (i.e., from the sin c²(x) function of Eqs. 3 & 4) has decayed to about 50% of its peak value. In particular, when x=1.39=η, sin c²(x)=0.5. However, other values for efficiency thresholds or factor in the Bragg envelope may be used if desired.

The beams 26-36 are imaged onto the CCD camera 60 to produce the pattern of light and dark regions 120-132 representing a digital (or binary) code, where light=1 and dark=0 (or vice versa). The digital code may be generated by selectively creating individual index variations (or individual gratings) with the desired spatial periods Λ1-Λn. Other illumination, readout techniques, types of gratings, geometries, materials, etc. may be used as discussed in the aforementioned patent application.

Referring to FIG. 30, illustrations (a)-(c), for the grating 12 in a cylindrical substrate 10 having a sample spectral 17 bit code (i.e., 17 different pitches Λ1-Λ17), the corresponding image on the CCD (Charge Coupled Device) camera 60 is shown for a digital pattern 17 bit locations 89, including FIG. 30 illustrations (b), (c) and (d), respectively, of 7 bits turned on (10110010001001001); 9 bits turned on of (11000101010100111); and all 17 bits turned on of (11111111111111111).

For the images in FIG. 30, the length of the substrate 10 was 450 microns, the outer diameter D1 was 65 microns, the inner diameter D was 14 microns, δn for the grating 12 was about 10⁻⁴, n1 in portion 20 was about 1.458 (at a wavelength of about 1550 nm), n2 in portion 18 was about 1.453, the average pitch spacing Λ for the grating 12 was about 0.542 microns, and the spacing between pitches ΔΛ was about 0.36% of the adjacent pitches Λ.

Referring to FIG. 31 illustration (a), the pitch Λ of an individual grating is the axial spatial period of the sinusoidal variation in the refractive index n1 in the region of the substrate 10 along the axial length of the grating 12 as indicated by a curve 90 on a graph 91. Referring to FIG. 31, illustration (b), a sample composite grating 12 comprises three individual gratings that are co-located on the substrate 10, each individual grating having slightly different pitches, Λ1, Λ2, Λ3, respectively, and the difference (or spacing) ΔΛ between each pitch Λ being about 3.0% of the period of an adjacent pitch Λ as indicated by a series of curves 92 on a graph 94. Referring to FIG. 31 illustration (c), three individual gratings, each having slightly different pitches, Λ1, Λ2, Λ3, respectively, are shown, the difference ΔΛ between each pitch Λ being about 0.3% of the pitch Λ of the adjacent pitch as shown by a series of curves 95 on a graph 97. The individual gratings in FIG. 31, illustrations (b) and (c) are shown to all start at 0 for illustration purposes however, it should be understood that, the separate gratings need not all start in phase with each other. Referring to FIG. 31, illustration (d), the overlapping of the individual sinusoidal refractive index variation pitches Λ1-Λn in the grating region 20 of the substrate 10, produces a combined resultant refractive index variation in the composite grating 12 shown as a curve 96 on a graph 98 representing the combination of the three pitches shown in FIG. 31, illustration (b). Accordingly, the resultant refractive index variation in the grating region 20 of the substrate 10 may not be sinusoidal and is a combination of the individual pitches Λ (or index variation).

The maximum number of resolvable bits N, which is equal to the number of different grating pitches Λ (and hence the number of codes), that can be accurately read (or resolved) using side-illumination and side-reading of the grating 12 in the substrate 10, is determined by numerous factors, including: the beam width w incident on the substrate (and the corresponding substrate length L and grating length Lg), the thickness or diameter D of the grating 12, the wavelength λ of incident light, the beam divergence angle θ_R, and the width of the Bragg envelope θ_B(discussed more in the aforementioned patent application), and may be determined by the equation:

$\begin{matrix} N ≅ \frac{η β L}{2 D \sin (θ_{i})} & Eq . 6 \end{matrix}$

Referring to FIG. 32, instead of having the input light 24 at a single wavelength λ (monochromatic) and reading the bits by the angle θo of the output light, the bits (or grating pitches Λ) may be read/detected by providing a plurality of wavelengths and reading the wavelength spectrum of the reflected output light signal. In this case, there would be one bit per wavelength, and thus, the code is contained in the wavelength information of the reflected output signal.

In this case, each bit (or Λ) is defined by whether its corresponding wavelength falls within the Bragg envelope, not by its angular position within the Bragg envelope 200. As a result, it is not limited by the number of angles that can fit in the Bragg envelope 200 for a given composite grating 12, as in the embodiment discussed hereinbefore. Thus, using multiple wavelengths, the only limitation in the number of bits N is the maximum number of grating pitches A that can be superimposed and optically distinguished in wavelength space for the output beam.

Referring to FIGS. 32 and 33, illustration (a), the reflection wavelength spectrum (λ1-λn) of the reflected output beam 310 will exhibit a series of reflection peaks 695, each appearing at the same output Bragg angle θo. Each wavelength peak 695 (λ1-λn) corresponds to an associated spatial period (Λ1-Λn), which make up the grating 12.

One way to measure the bits in wavelength space is to have the input light angle θi equal to the output light angle θo, which is kept at a constant value, and to provide an input wavelength λ that satisfies the diffraction condition (Eq. 1) for each grating pitch Λ. This will maximize the optical power of the output signal for each pitch Λ detected in the grating 12.

Referring to 33, illustration (b), the transmission wavelength spectrum of the transmitted output beam 330 (which is transmitted straight through the grating 12) will exhibit a series of notches (or dark spots) 696. Alternatively, instead of detecting the reflected output light 310, the transmitted light 330 may be detected at the detector/reader 308. It should be understood that the optical signal levels for the reflection peaks 695 and transmission notches 696 will depend on the “strength” of the grating 12, i.e., the magnitude of the index variation n in the grating 12.

In FIG. 32, the bits may be detected by continuously scanning the input wavelength. A known optical source 300 provides the input light signal 24 of a coherent scanned wavelength input light shown as a graph 304. The source 300 provides a sync signal on a line 306 to a known reader 308. The sync signal may be a timed pulse or a voltage ramped signal, which is indicative of the wavelength being provided as the input light 24 to the substrate 10 at any given time. The reader 308 may be a photodiode, CCD camera, or other optical detection device that detects when an optical signal is present and provides an output signal on a line 309 indicative of the code in the substrate 10 or of the wavelengths present in the output light, which is directly related to the code, as discussed herein. The grating 12 reflects the input light 24 and provides an output light signal 310 to the reader 308. The wavelength of the input signal is set such that the reflected output light 310 through an optical lens 321 will be substantially in the center 314 of the Bragg envelope 200 for the individual grating pitch (or bit) being read.

Alternatively, the source 300 may provide a continuous broadband wavelength input signal such as that shown as a graph 316. In that case, the reflected output beam 310 signal is provided to a narrow band scanning filter 318 which scans across the desired range of wavelengths and provides a filtered output optical signal 320 to the reader 308. The filter 318 provides a sync signal on a line 322 to the reader, which is indicative of which wavelengths are being provided on the output signal 320 to the reader and may be similar to the sync signal discussed hereinbefore on the line 306 from the source 300. In this case, the source 300 does not need to provide a sync signal because the input optical signal 24 is continuous. Alternatively, instead of having the scanning filter being located in the path of the output beam 310, the scanning filter may be located in the path of the input beam 24 as indicated by the dashed box 324, which provides the sync signal on a line 323.

Alternatively, instead of the scanning filters 318,324, the reader 308 may be a known optical spectrometer (such as a known spectrum analyzer), capable of measuring the wavelength of the output light.

The desired values for the input wavelengths λ (or wavelength range) for the input signal 24 from the source 300 may be determined from the Bragg condition of Eq. 1, for a given grating spacing Λ and equal angles for the input light θi and the angle light θo. Solving Eq. 1 for λ and plugging in m=1, gives:

λ=Λ[sin(θo)+sin(θi)] Eq. 7

It is also possible to combine the angular-based code detection with the wavelength-based code detection, both discussed hereinbefore. In this case, each readout wavelength is associated with a predetermined number of bits within the Bragg envelope. Bits (or grating pitches Λ) written for different wavelengths do not show up unless the correct wavelength is used.

Accordingly, the bits (or grating pitches Λ) can be read using one wavelength and many angles, many wavelengths and one angle, or many wavelengths and many angles.

Referring to FIG. 34, the grating 12 may have a thickness or depth D which is comparable or smaller than the incident beam wavelength λ. This is known as a “thin” diffraction grating (or the full angle Bragg envelope is 180 degrees). In that case, the half-angle Bragg envelope θB is substantially 90 degrees however, δn must be made large enough to provide sufficient reflection efficiency per Eqs. 3 and 4. In particular, for a “thin” grating, D*δn≈λ/2, which corresponds to a π phase shift between adjacent minimum and maximum refractive index values of the grating 12.

It should be understood that there is still a trade-off discussed hereinbefore with beam divergence angle θ_Rand the incident beam width (or length L of the substrate), but the accessible angular space is theoretically now 90 degrees. Also, for maximum efficiency the phase shift between adjacent minimum and maximum refractive index values of the grating 12 should approach a π phase shift however, other phase shifts may be used.

In this case, rather than having the input light 24 coming in at the conventional Bragg input angle θi, as discussed hereinbefore and indicated by a dashed line 701, the grating 12 is illuminated with the input light 24 oriented on a line 705 orthogonal to the longitudinal grating vector 703. The input beam 24 will split into two (or more) beams of equal amplitude, where the exit angle θ_ocan be determined from Eq. 1 with the input angle θ_i=0 (normal to the longitudinal axis of the grating 12).

In particular, from Eq. 1, for a given grating pitch Λ1, the +/−1^storder beams (m=+1 and m=−1) corresponds to output beams 700,702, respectively, the +/−2^ndorder beams (m=+2 and m=−2) corresponds to output beams 704,706, respectively; and the 0^thorder (undiffracted) beam (m=0) corresponds to beam 708 and passes straight through the substrate. The output beams 700-708 project spectral spots or peaks 710-718, respectively, along a common plane, shown from the side by a line 709, which is parallel to the upper surface of the substrate 10.

For example, for a grating pitch Λ=1.0 um, and an input wavelength λ=400 nm, the exit angles θ_oare ˜+/−23.6 degrees (for m=+/−1), and +/−53.1 degrees (from m=+/−2), from Eq. 1. It should be understood that for certain wavelengths, certain orders (e.g., m=+/−2) may be reflected back toward the input side or otherwise not detectable at the output side of the grating 12.

Alternatively, one can use only the +/−1^storder (m=+/−1) output beams for the code, in which case there would be only 2 peaks to detect, 712, 714. Alternatively, one can also use any one or more pairs from any order output beam that is capable of being detected. Alternatively, instead of using a pair of output peaks for a given order, an individual peak may be used.

Referring to FIG. 35, if two pitches Λ1,Λ2 exist in the grating 12, two sets of peaks will exist. In particular, for a second grating pitch Λ2, the +/−1^storder beams (m=+1 and m=−1) corresponds to output beams 720,722, respectively, the +/−2^ndorder beams (m=+2 and m=−2) corresponds to output beams 724,726, respectively, and the 0^thorder (un-diffracted) beam (m=0) corresponds to beam 718 and passes straight through the substrate. The output beams 720-726 corresponding to the second pitch Λ2 project spectral spots or peaks 730-736, respectively, which are at a different location than the point 710-716, but along the same common plane, shown from the side by the line 709.

Thus, for a given pitch Λ (or bit) in a grating, a set of spectral peaks will appear at a specific location in space. Thus, each different pitch corresponds to a different elevation or output angle which corresponds to a predetermined set of spectral peaks. Accordingly the presence or absence of a particular peak or set of spectral peaks defines the code.

In general, if the angle of the grating 12 is not properly aligned with respect to the mechanical longitudinal axis of the substrate 10, the readout angles may no longer be symmetric, leading to possible difficulties in readout. With a thin grating, the angular sensitivity to the alignment of the longitudinal axis of the substrate 10 to the input angle θi of incident radiation is reduced or eliminated. In particular, the input light can be oriented along substantially any angle θi with respect to the grating 12 without causing output signal degradation, due the large Bragg angle envelope. Also, if the incident beam 24 is normal to the substrate 10, the grating 12 can be oriented at any rotational (or azimuthal) angle without causing output signal degradation. However, in each of these cases, changing the incident angle θi will affect the output angle θo of the reflected light in a predetermined predictable way, thereby allowing for accurate output code signal detection or compensation.

Referring to FIG. 36, for a thin grating, in addition to multiplexing in the elevation or output angle based on grating pitch Λ, the bits can also be multiplexed in an azimuthal (or rotational) angle θa of the substrate. In particular, a plurality of gratings 750,752,754,756 each having the same pitch Λ are disposed in a surface 701 of the substrate 10 and located in the plane of the substrate surface 701. The input light 24 is incident on all the gratings 750,752,754,756 simultaneously. Each of the gratings provides output beams oriented based on the grating orientation. For example, the grating 750 provides the output beams 764,762, the grating 752 provides the output beams 766,768, the grating 754 provides the output beams 770,772, and the grating 756 provides the output beams 774,776. Each of the output beams provides spectral peaks or spots (similar to that discussed hereinbefore), which are located in a plane 760 that is parallel to the substrate surface plane 701. In this case, a single grating pitch Λ can produce many bits depending on the number of gratings that can be placed at different azimuthal (rotational) angles on the surface of the substrate 10 and the number of output beam spectral peaks that can be spatially and optically resolved/detected. Each bit may be viewed as the presence or absence of a pair of peaks located at a predetermined location in space in the plane 760. Note that this example uses only the m=+/−1^storder for each reflected output beam. Alternatively, the detection may also use the m=+/−2^ndorder. In that case, there would be two additional output beams and peaks (not shown) for each grating (as discussed hereinbefore) that may lie in the same plane as the plane 760 and may be on a concentric circle outside the circle 760.

In addition, the azimuthal multiplexing can be combined with the elevation or output angle multiplexing discussed hereinbefore to provide two levels of multiplexing. Accordingly for a thin grating, the number of bits can be multiplexed based on the number of grating pitches Λ and/or geometrically by the orientation of the grating pitches.

Furthermore, if the input light angle θi is normal to the substrate 10, the edges of the substrate 10 no longer scatter light from the incident angle into the “code angular space”, as discussed herein and/or in the aforementioned patent application.

Also, in the thin grating geometry, a continuous broadband wavelength source may be used as the optical source if desired.

Referring to FIG. 37, instead of or in addition to the pitches A in the grating 12 being oriented normal to the longitudinal axis, the pitches may be created at a angle θg. In that case, when the input light 24 is incident normal to the surface 792, will produce a reflected output beam 790 having an angle θo determined by Eq. 1 as adjusted for the blaze angle θg. This can provide another level of multiplexing bits in the code.

Referring to FIG. 38, instead of using an optical binary (0-1) code, an additional level of multiplexing may be provided by having the optical code use other numerical bases, if intensity levels of each bit are used to indicate code information. This could be achieved by having a corresponding magnitude (or strength) of the refractive index change (δn) for each grating pitch Λ. Four intensity ranges are shown for each bit number or pitch Λ, providing for a Base-4 code (where each bit corresponds to 0,1,2, or 3). The lowest intensity level, corresponding to a 0, would exist when this pitch Λ is not present in the grating 12. The next intensity level 450 would occur when a first low level δn1 exists in the grating that provides an output signal within the intensity range corresponding to a 1. The next intensity level 452 would occur when a second higher level δn2 exists in the grating 12 that provides an output signal within the intensity range corresponding to a 2. The next intensity level 454 would occur when a third higher level δn3 exists in the grating 12 that provides an output signal within the intensity range corresponding to a 3.

Referring to FIG. 39, the input light 24 may be incident on the substrate 10 on an end face 600 of the substrate 10. In that case, the input light 24 will be incident on the grating 12 having a more significant component of the light (as compared to side illumination discussed hereinbefore) along the longitudinal grating axis 207 of the grating (along the grating vector k_B), as shown by a line 602. The light 602 reflects off the grating 12 as indicated by a line 604 and exits the substrate as output light 608. Accordingly it should be understood by one skilled in the art that the diffraction equations discussed hereinbefore regarding output diffraction angle θo also apply in this case except that the reference axis would now be the grating axis 207. Thus, in this case, the input and output light angles θi,θo, would be measured from the grating axis 207 and length Lg of the grating 12 would become the thickness or depth D of the grating 12. As a result, a grating 12 that is 400 microns long, would result in the Bragg envelope 200 being narrow. It should be understood that because the values of n1 and n2 are close to the same value, the slight angle changes of the light between the regions 18,20 are not shown herein.

In the case where incident light 610 is incident along the same direction as the grating vector (Kb) 207, i.e., θi=0 degrees, the incident light sees the whole length Lg of the grating 12 and the grating provides a reflected output light angle θo=0 degrees, and the Bragg envelope 612 becomes extremely narrow, as the narrowing effect discussed above reaches a limit. In that case, the relationship between a given pitch Λ in the grating 12 and the wavelength of reflection λ is governed by a known “Bragg grating” relation:

λ=2n_effΛ Eq. 8

where n_effis the effective index of refraction of the substrate, λ is the input (and output wavelength) and Λ is the pitch. This relation, as is known, may be derived from Eq. 1 where θi=θo=90 degrees.

In that case, the code information is readable only in the spectral wavelength of the reflected beam, similar to that discussed hereinbefore for wavelength based code reading. Accordingly the input signal in this case may be a scanned wavelength source or a broadband wavelength source. In addition, as discussed hereinbefore for wavelength based code reading, the code information may be obtained in reflection from the reflected beam 614 or in transmission by the transmitted beam 616 that passes through the grating 12.

It should be understood that for shapes of the substrate 10 or element 8 other than a cylinder, the effect of various different shapes on the propagation of input light through the element 8, substrate 10, and/or grating 12, and the associated reflection angles, can be determined using known optical physics including Snell's Law, shown below:

n_insin θin=n_outsin θout 9

where n_inis the refractive index of the first (input) medium, and n_outis the refractive index of the second (output) medium, and θin and θout are measured from a line 620 normal to an incident surface 622.

Referring to FIG. 40, if the value of nil in the grating region 20 is greater than the value of n2 in the non-grating region 18, the grating region 20 of the substrate 10 will act as a known optical waveguide for certain wavelengths. In that case, the grating region 20 acts as a “core” along which light is guided and the outer region 18 acts as a “cladding” which helps confine or guide the light. Also, such a waveguide will have a known “numerical aperture” (θna) that will allow light 630 that is within the aperture θna to be directed or guided along the grating axis 207 and reflected axially off the grating 12 and returned and guided along the waveguide. In that case, the grating 12 will reflect light having the appropriate wavelengths equal to the pitches Λ present in the grating 12 back along the region 20 (or core) of the waveguide, and pass the remaining wavelengths of light as the light 632. Thus, having the grating region 20 act as an optical waveguide for wavelengths reflected by the grating 12 allows incident light that is not aligned exactly with the grating axis 207 to be guided along and aligned with the grating 12 axis 207 for optimal grating reflection.

If an optical waveguide is used any standard waveguide may be used, e.g., a standard telecommunication single mode optical fiber (125 micron diameter or 80 micron diameter fiber with about a 8-10 micron diameter), or a larger diameter waveguide (greater than 0.5 mm diameter), such as is describe in U.S. patent application Ser. No. 09/455,868, filed Dec. 6, 1999, entitled “Large Diameter Waveguide, Grating”. Further, any type of optical waveguide may be used for the optical substrate 10, such as, a multi-mode, birefringent, polarization maintaining, polarizing, multi-core, multi-cladding, or microstructured optical waveguide, or a flat or planar waveguide (where the waveguide is rectangular shaped), or other waveguides.

Referring to FIG. 41 if the grating 12 extends across the entire dimension D of the substrate, the substrate 10 does not behave as a waveguide for the incident or reflected light and the incident light 24 will be diffracted (or reflected) as indicated by lines 642, and the codes detected as discussed hereinbefore for the end-incidence condition discussed hereinbefore with FIG. 45, and the remaining light 640 passes straight through.

Referring to FIG. 42, illustrations (a)-(c), in illustration (a), for the end illumination condition, if a blazed or angled grating is used, as discussed hereinbefore, the input light 24 is coupled out of the substrate 10 at a known angle as shown by a line 650. Referring to FIG. 42, illustration (b), alternatively, the input light 24 may be incident from the side and, if the grating 12 has the appropriate blaze angle, the reflected light will exit from the end face 652 as indicated by a line 654. Referring to FIG. 42, illustration (c), the grating 12 may have a plurality of different pitch angles 660,662, which reflect the input light 24 to different output angles as indicated by lines 664, 666. This provides another level of multiplexing (spatially) additional codes, if desired.

The grating 12 may be impressed in the substrate 10 by any technique for writing, impressed, embedded, imprinted, or otherwise forming a diffraction grating in the volume of or on a surface of a substrate 10. Examples of some known techniques are described in U.S. Pat. Nos. 4,725,110 and 4,807,950, entitled “Method for Impressing Gratings Within Fiber Optics”, to Glenn et al, and U.S. Pat. No. 5,388,173, entitled “Method and Apparatus for Forming Aperiodic Gratings in Optical Fibers”, to Glenn, respectively, and U.S. Pat. No. 5,367,588, entitled “Method of Fabricating Bragg Gratings Using a Silica Glass Phase Grating Mask and Mask Used by Same”, to Hill, and U.S. Pat. No. 3,916,182, entitled “Periodic Dielectric Waveguide Filter”, Dabby et al, and U.S. Pat. No. 3,891,302, entitled “Method of Filtering Modes in Optical Waveguides”, to Dabby et al, which are all incorporated herein by reference to the extent necessary to understand the present invention.

Alternatively, instead of the grating 12 being impressed within the substrate material, the grating 12 may be partially or totally created by etching or otherwise altering the outer surface geometry of the substrate to create a corrugated or carving surface geometry of the substrate, such as is described in U.S. Pat. No. 3,891,302, entitled “Method of Filtering Modes in Optical Waveguides”, to Dabby et al, which is incorporated herein by reference to the extent necessary to understand the present invention, provided the resultant optical refractive profile for the desired code is created.

The substrate 10 (and/or the element 8) may have end-view cross-sectional shapes other than circular, such as square, rectangular, elliptical, clam-shell, D-shaped, or other shapes, and may have side-view sectional shapes other than rectangular, such as circular, square, elliptical, clam-shell, D-shaped, or other shapes. Also, 3D geometries other than a cylinder may be used, such as a sphere, a cube, a pyramid or any other 3D shape. Alternatively, the substrate 10 may have a geometry that is a combination of one or more of the foregoing shapes.

The shape of the element 8 and the size of the incident beam may be made to minimize any end scatter off the end face(s) of the element 8, as is discussed herein and/or in the aforementioned patent application. Accordingly to minimize such scatter, the incident beam 24 may be oval shaped where the narrow portion of the oval is smaller than the diameter D1, and the long portion of the oval is smaller than the length L of the element 8. Alternatively, the shape of the end faces may be rounded or other shapes or may be coated with an antireflective coating.

It should be understood that the size of any given dimension for the region 20 of the grating 12 may be less than any corresponding dimension of the substrate 10. For example, if the grating 12 has dimensions of length Lg, depth Dg, and width Wg, and the substrate 12 has different dimensions of length L, depth D, and width W, the dimensions of the grating 12 may be less than that of the substrate 12. Thus, the grating 12, may be embedded within or part of a much larger substrate 12. Also, the element 8 may be embedded or formed in or on a larger object for identification of the object.

The dimensions, geometries, materials, and material properties of the substrate 10 are selected such that the desired optical and material properties are met for a given application. The resolution and range for the optical codes are scalable by controlling these parameters as discussed herein and/or in the aforementioned patent application.

Referring to FIG. 43, the substrate 10 may have an outer coating 799, such as a polymer or other material that may be dissimilar to the material of the substrate 10, provided that the coating 799 on at least a portion of the substrate, allows sufficient light to pass through the substrate for adequate optical detection of the code. The coating 799 may be on any one or more sides of the substrate 10. Also, the coating 799 may be a material that causes the element 8 to float or sink in certain fluids (liquid and/or gas) solutions.

Also, the substrate 10 may be made of a material that is less dense than certain fluid (liquids and/or gas) solutions, thereby allowing the elements 8 to float or be buoyant or partially buoyant. Also, the substrate may be made of a porous material, such as controlled pore glass (CPG) or other porous material, which may also reduce the density of the element 8 and may make the element 8 buoyant or partially-buoyant in certain fluids.

Referring to FIG. 44, the grating 12 is axially spatially invariant. As a result, the substrate 10 with the grating 12 (shown as a long substrate 21) may be axially subdivided or cut into many separate smaller substrates 30-36 and each substrate 30-36 will contain the same code as the longer substrate 21 had before it was cut. The limit on the size of the smaller substrates 30-36 is based on design and performance factors discussed herein and/or in the aforementioned patent application.

Referring to FIG. 45, one purpose of the outer region 18 (or region without the grating 12) of the substrate 10 is to provide mechanical or structural support for the inner grating region 20. Accordingly the entire substrate 10 may comprise the grating 12, if desired. Alternatively, the support portion may be completely or partially beneath, above, or along one or more sides of the grating region 20, such as in a planar geometry, or a D-shaped geometry, or other geometries, as described herein and/or in the aforementioned patent application. The non-grating portion 18 of the substrate 10 may be used for other purposes as well, such as optical lensing effects or other effects (discussed herein or in the aforementioned patent application). Also, the end faces of the substrate 10 need not be perpendicular to the sides or parallel to each other. However, for applications where the elements 8 are stacked end-to-end, the packing density may be optimized if the end faces are perpendicular to the sides.

Referring to FIG. 46, illustrations (a)-(c), two or more substrates 10,250, each having at least one grating therein, may be attached together to form the element 8, e.g., by an adhesive, fusing or other attachment techniques. In that case, the gratings 12,252 may have the same or different codes.

Referring to FIG. 47, illustrations (a) and (b), the substrate 10 may have multiple regions 80,90 and one or more of these regions may have gratings in them. For example, there may be gratings 12,252 side-by-side (illustration (a)), or there may be gratings 82-88, spaced end-to-end (illustration (b)) in the substrate 10.

Referring to FIG. 48, the length L of the element 8 may be shorter than its diameter D, thus, having a geometry such as a plug, puck, wafer, disc or plate.

Referring to FIG. 49, to facilitate proper alignment of the grating axis with the angle θi of the input beam 24, the substrate 10 may have a plurality of the gratings 12 having the same codes written therein at numerous different angular or rotational (or azimuthal) positions of the substrate 10. In particular, two gratings 550, 552, having axial grating axes 551, 553, respectively may have a common central (or pivot or rotational) point where the two axes 551,553 intersect. The angle θi of the incident light 24 is aligned properly with the grating 550 and is not aligned with the grating 552, such that output light 555 is reflected off the grating 550 and light 557 passes through the grating 550 as discussed herein. If the element 8 is rotated as shown by the arrows 559, the angle θi of incident light 24 will become aligned properly with the grating 552 and not aligned with the grating 550 such that output light 555 is reflected off the grating 552 and light 557 passes through the grating 552. When multiple gratings are located in this rotational orientation, the bead may be rotated as indicated by a line 559 and there may be many angular positions that will provide correct (or optimal) incident input angles θi to the grating. While this example shows a circular cross-section, this technique may be used with any shape cross-section.

Referring to FIG. 50, illustrations (a), (b), (c), (d), and (e) the substrate 10 may have one or more holes located within the substrate 10. In illustration (a), holes 560 may be located at various points along all or a portion of the length of the substrate 10. The holes need not pass all the way through the substrate 10. Any number, size and spacing for the holes 560 may be used if desired. In illustration (b), holes 572 may be located very close together to form a honeycomb-like area of all or a portion of the cross-section. In illustration (c), one (or more) inner hole 566 may be located in the center of the substrate 10 or anywhere inside of where the grating region(s) 20 are located. The inner hole 566 may be coated with a reflective coating 573 to reflect light to facilitate reading of one or more of the gratings 12 and/or to reflect light diffracted off one or more of the gratings 12. The incident light 24 may reflect off the grating 12 in the region 20 and then reflect off the surface 573 to provide output light 577. Alternatively, the incident light 24 may reflect off the surface 573, then reflect off the grating 12 and provide the output light 575. In that case the grating region 20 may run axially or circumferentially 571 around the substrate 10. In illustration (d), the holes 579 may be located circumferentially around the grating region 20 or transversely across the substrate 10. In illustration (e), the grating 12 may be located circumferentially around the outside of the substrate 10, and there may be holes 574 inside the substrate 10. In that case, the incident light 24 reflects off the grating 12 to provide the optical light 576.

Referring to FIG. 51, illustrations (a), (b), and (c), the substrate 10 may have one or more protruding portions or teeth 570, 578,580 extending radially and/or circumferentially from the substrate 10. Alternatively, the teeth 570, 578,580 may have any other desired shape.

Referring to FIG. 52, illustrations (a), (b), (c) a D-shaped substrate, a flat-sided substrate and an eve-shaped (or clam-shell or teardrop shaped) substrate 10, respectively, are shown. Also, the grating region 20 may have end cross-sectional shapes other than circular and may have side cross-sectional shapes other than rectangular, such as any of the geometries described herein for the substrate 10. For example, the grating region 20 may have an oval cross-sectional shape as shown by dashed lines 581, which may be oriented in a desired direction, consistent with the teachings herein. Any other geometries for the substrate 10 or the grating region 20 may be used if desired, as described herein.

Referring to FIG. 53, at least a portion of a side of the substrate 10 may be coated with a reflective coating 514 to allows incident light 510 to be reflected back to the same side from which the incident light came, as indicated by reflected light 512.

Referring to FIG. 54, illustrations (a) and (b), alternatively, the substrate 10 can be electrically and/or magnetically polarized, by a dopant or coating, which may be used to ease handling and/or alignment or orientation of the substrate 10 and/or the grating 12, or used for other purposes. Alternatively, the bead may be coated with conductive material, e.g., metal coating on the inside of a holey substrate, or metallic dopant inside the substrate. In these cases, such materials can cause the substrate 10 to align in an electric or magnetic field. Alternatively, the substrate can be doped with an element or compound that fluoresces or glows under appropriate illumination, e.g., a rare earth dopant, such as Erbium, or other rare earth dopant or fluorescent or luminescent molecule. In that case, such fluorescence or luminescence may aid in locating and/or aligning substrates.

The dimensions and/or geometries for any of the embodiments described herein are merely for illustrative purposes and, as such, any other dimensions and/or geometries may be used if desired, depending on the application, size, performance, manufacturing requirements, or other factors, in view of the teachings herein.

It should be understood that, unless stated otherwise herein, any of the features, characteristics, alternatives or modifications described regarding a particular embodiment herein may also be applied, used, or incorporated with any other embodiment described herein. Also, the drawings herein are not drawn to scale.

Although the invention has been described and illustrated with respect to exemplary embodiments thereof, the foregoing and various other additions and omissions may be made therein and thereto without departing from the spirit and scope of the present invention.

Claims

1. A system for writing an optical code within or on a fiber substrate, the system comprising: a holding device having a plurality of supports spaced apart from each other, the fiber substrate being wound about the supports such that the fiber substrate forms at least one flat section extending between adjacent supports, wherein the fiber substrate is configured to be wound about the supports a plurality of times to form a fiber ribbon; andat least one light source configured to write an optical code within or on the flat section of the fiber substrate.
2. A system in accordance with claim 1 wherein the holding device includes a plurality of openings, each opening formed between adjacent supports.
3. A system in accordance with claim 1 wherein the holding device includes a plate, the supports extending from the plate and parallel with respect to each other.
4. A system in accordance with claim 1 wherein the holding device has a generally polygonal shape.
5. A system in accordance with claim 1 wherein the holding device includes a disk, the fiber substrate being wound about an outer circumference of the disk.
6. A system in accordance with claim 5 wherein the disk includes a plurality of circumferentially spaced slots, the fiber substrate extending across each slot.
7. A system in accordance with claim 1 wherein the holding device is configured to rotate about an axis, the supports extending parallel to the axis and rotating about the axis.
8. A system in accordance with claim 1 wherein the fiber substrate forms a generally polygonal shape when the fiber substrate is wound about the holding device.
9. A system in accordance with claim 1 wherein the plurality of supports include a plurality of rods.
10. A system in accordance with claim 1 further comprising a phase mask configured such that light from the light source passes through the phase mask to write the optical code.
11. A system in accordance with claim 1 wherein the light source is configured to write a diffraction grating within the fiber substrate.
12. A system in accordance with claim 1 wherein the light source comprises only a single laser or a pair of lasers.
13. A system in accordance with claim 1 further comprising the fiber substrate.
14. A system in accordance with claim 1 wherein the holding device is moveable relative to the light source, the supports and the fiber substrate being configured to have a fixed position with respect to each other when the holding device is moved.
15. A method for writing an optical code within or on a fiber substrate, the method comprising: providing a holding device, the holding device having a plurality of supports spaced apart from each other;winding the fiber substrate about the holding device, the fiber substrate being wound about the supports such that the fiber substrate forms at least one flat section extending between adjacent supports, wherein the fiber substrate forms a generally polygonal shape having a plurality of flat sections when the fiber substrate is wound about the holding device; andproviding a light beam to the flat sections of the fiber substrate to write optical codes within or on the fiber substrate.
16. A method in accordance with claim 15 wherein the holding device is configured to be rotated about an axis to position the flat sections for writing.
17. A method in accordance with claim 15 wherein each of the flat sections is written with a different code.
18. A method in accordance with claim 15 wherein the adjacent supports includes pairs of adjacent supports, the fiber substrate being wound a plurality of times about the holding device such that each pair of adjacent supports has a plurality of flat sections extending therebetween.
19. A method in accordance with claim 15 wherein said winding the fiber substrate includes winding the fiber substrate a plurality of times about the holding device to form a plurality of wraps, each wrap of the fiber substrate being adjacent to other wraps of the fiber substrate.
20. A method in accordance with claim 15 wherein the light beam is split to provide interfering beams or the light beam is passed through a phase mask.
21. A method in accordance with claim 15 further comprising: moving the holding device relative to a light source that provides the light beam, wherein the supports and the fiber substrate have a fixed position with respect to each other when the holding device is moved.
22. A method for writing an optical code within or on a fiber substrate, the method comprising: providing a holding device, the holding device having a plurality of supports spaced apart from each other;winding the fiber substrate about the holding device, the fiber substrate being wound about the supports such that the fiber substrate forms at least one flat section extending between adjacent supports, the fiber substrate being wound a plurality of times about the supports; andproviding a light beam to the flat section of the fiber substrate to write an optical code within or on the fiber substrate.
23. A method in accordance with claim 22 wherein the holding device is configured to be rotated about an axis.
24. A method in accordance with claim 22 wherein the fiber substrate forms a generally polygonal shape having a plurality of flat sections when the fiber substrate is wound about the holding device.
25. A method in accordance with claim 24 wherein the light beam is provided to the flat sections to write optical codes within or on the fiber substrate.
26. A method in accordance with claim 24 wherein each of the flat sections is written with a different code.
27. A method in accordance with claim 22 further comprising providing a phase mask, the light beam passing through the phase mask to form the optical code.
28. A method in accordance with claim 22 wherein the fiber substrate has a plurality of wraps about the supports, each wrap of the fiber substrate being adjacent to other wraps of the fiber substrate.
29. A method in accordance with claim 22 further comprising: moving the holding device relative to a light source that provides the light beam, wherein the supports and the fiber substrate have a fixed position with respect to each other when the holding device is moved.
30. A method in accordance with claim 22 wherein the light beam is split to provide interfering beams or the light beam is passed through a phase mask.
31. A system for writing an optical code within or on a fiber substrate, the system comprising: a holding device having a plurality of supports spaced apart from each other, the supports being arranged so that the fiber substrate forms a generally polygonal shape when wound about the supports and has a plurality of flat sections that extend between adjacent supports; andat least one light source configured to write optical codes within or on the flat sections of the fiber substrate.
32. A system in accordance with claim 31 wherein the holding device is moveable relative to the light source, the supports and the fiber substrate being configured to have a fixed position with respect to each other when the holding device is moved.
33. A system in accordance with claim 31 wherein the holding device includes a plate, the supports extending from the plate and parallel with respect to each other.
34. A system in accordance with claim 31 wherein the holding device includes a disk, the fiber substrate being wound about an outer circumference of the disk.
35. A system in accordance with claim 31 wherein the holding device is configured to rotate about an axis, the supports extending parallel to the axis and rotating about the axis.
36. A system in accordance with claim 31 wherein the plurality of supports include a plurality of rods.
37. A system in accordance with claim 31 further comprising a phase mask positioned so that light from the light source passes through the phase mask to write the optical code.
38. A system in accordance with claim 31 further comprising the fiber substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims benefit to U.S. patent application Ser. No. 11/454,307, filed on Jun. 16, 2006, which is a continuation of U.S. patent application Ser. No. 10/661,116, filed on Sep. 12, 2003, which is a continuation in part of Ser. No. 10/645,689, filed on Aug. 20, 2003 and claims benefit to U.S. Provisional Patent Application No. 60/410,541, filed on Sep. 12, 2002, all of which are incorporated by reference in their entirety. U.S. patent application Ser. No. 10/661,234 and application Ser. No. 10/661,082, were filed contemporaneously with the parent application, contains subject matter related to that disclosed herein, which is incorporated by reference in its entirety.

US Referenced Citations (443)

Number	Name	Date	Kind
3074634	Gamo	Jan 1963	A
3600223	Glick	Aug 1971	A
3614193	Beiser	Oct 1971	A
3791788	Taylor	Feb 1974	A
3858979	Elbe	Jan 1975	A
3880497	Bryngdahl	Apr 1975	A
3891302	Dabby et al.	Jun 1975	A
3903415	Holzapfel	Sep 1975	A
3916182	Dabby et al.	Oct 1975	A
3928253	Thornton et al.	Dec 1975	A
3968476	McMahon	Jul 1976	A
4011435	Phelps	Mar 1977	A
4023010	Horst et al.	May 1977	A
4053228	Schiller	Oct 1977	A
4053433	Lee	Oct 1977	A
4112037	Parker et al.	Sep 1978	A
4131337	Moraw et al.	Dec 1978	A
4168146	Grubb et al.	Sep 1979	A
4301139	Feingers et al.	Nov 1981	A
4386274	Altshuler	May 1983	A
4400616	Chevillat et al.	Aug 1983	A
4445229	Tasto et al.	Apr 1984	A
4447546	Hirschfeld	May 1984	A
4537504	Baltes et al.	Aug 1985	A
4560881	Briggs	Dec 1985	A
4562157	Lowe et al.	Dec 1985	A
4647544	Nicoli et al.	Mar 1987	A
4678752	Thorne et al.	Jul 1987	A
4685480	Eck	Aug 1987	A
4688240	Hosemann	Aug 1987	A
4690907	Hibino et al.	Sep 1987	A
4701754	Provonchee	Oct 1987	A
4716121	Block et al.	Dec 1987	A
4725110	Glenn et al.	Feb 1988	A
4740468	Weng et al.	Apr 1988	A
4740688	Edwards	Apr 1988	A
4748110	Paul	May 1988	A
4762420	Bowley	Aug 1988	A
4767719	Finlan	Aug 1988	A
4770295	Carveth	Sep 1988	A
4807950	Glenn et al.	Feb 1989	A
4815027	Tokumitsu	Mar 1989	A
4816659	Bianco et al.	Mar 1989	A
4820006	Constant	Apr 1989	A
4822746	Walt	Apr 1989	A
4841140	Sullivan et al.	Jun 1989	A
4843631	Steinpichler	Jun 1989	A
4877747	Stewart	Oct 1989	A
4880752	Keck et al.	Nov 1989	A
4882288	North et al.	Nov 1989	A
4921805	Gebeyehu et al.	May 1990	A
4931384	Layton	Jun 1990	A
4937048	Sakai et al.	Jun 1990	A
4958376	Leib	Sep 1990	A
4992385	Godfrey	Feb 1991	A
5002867	Macevicz	Mar 1991	A
5003600	Deason et al.	Mar 1991	A
RE33581	Nicoli et al.	Apr 1991	E
5028545	Soini	Jul 1991	A
5030558	Litman et al.	Jul 1991	A
5033826	Kolner	Jul 1991	A
5048139	Matsumi	Sep 1991	A
5065008	Hakamata et al.	Nov 1991	A
5067155	Bianco et al.	Nov 1991	A
5081012	Flanagan et al.	Jan 1992	A
5089387	Tsay et al.	Feb 1992	A
5090807	Tai	Feb 1992	A
5091636	Takada et al.	Feb 1992	A
5095194	Barbanell	Mar 1992	A
5100238	Nailor et al.	Mar 1992	A
5104209	Hill et al.	Apr 1992	A
5105305	Betzig et al.	Apr 1992	A
5114864	Walt	May 1992	A
5115121	Bianco et al.	May 1992	A
5118608	Layton et al.	Jun 1992	A
5129974	Aurenius	Jul 1992	A
5138468	Barbanell	Aug 1992	A
5141848	Donovan et al.	Aug 1992	A
5143853	Walt	Sep 1992	A
5144461	Horan	Sep 1992	A
5160701	Brown, III et al.	Nov 1992	A
5166813	Metz	Nov 1992	A
5192980	Dixon et al.	Mar 1993	A
5196350	Backman et al.	Mar 1993	A
5200794	Nishiguma et al.	Apr 1993	A
5218594	Tanno	Jun 1993	A
5239178	Derndinger	Aug 1993	A
5244636	Walt et al.	Sep 1993	A
5283777	Tanno et al.	Feb 1994	A
5291006	Nishiguma et al.	Mar 1994	A
5291027	Kita et al.	Mar 1994	A
5300764	Hoshino et al.	Apr 1994	A
5307332	Tinet	Apr 1994	A
5310686	Sawyers et al.	May 1994	A
5329352	Jacobsen	Jul 1994	A
5342790	Levine et al.	Aug 1994	A
5349442	Deason et al.	Sep 1994	A
5352582	Lichtenwalter et al.	Oct 1994	A
5364797	Olson et al.	Nov 1994	A
5367588	Hill et al.	Nov 1994	A
5372783	Lackie	Dec 1994	A
5374816	Bianco	Dec 1994	A
5374818	Bianco et al.	Dec 1994	A
5388173	Glenn	Feb 1995	A
5394234	Bianco et al.	Feb 1995	A
5395558	Tsai	Mar 1995	A
5410147	Riza	Apr 1995	A
5426297	Dunphy et al.	Jun 1995	A
5432329	O'Boyle et al.	Jul 1995	A
5442433	Hoshino et al.	Aug 1995	A
5448659	Tsutsui et al.	Sep 1995	A
5451528	Raymoure et al.	Sep 1995	A
5455178	Fattinger	Oct 1995	A
5461475	Lerner et al.	Oct 1995	A
5465176	Bianco et al.	Nov 1995	A
5468649	Shah et al.	Nov 1995	A
5472515	Roberts	Dec 1995	A
5506674	Inoue et al.	Apr 1996	A
5514785	Van Ness et al.	May 1996	A
5528045	Hoffman et al.	Jun 1996	A
5547849	Baer et al.	Aug 1996	A
5559613	Deveaud-Pledran et al.	Sep 1996	A
5585639	Dorsel et al.	Dec 1996	A
5587832	Krause	Dec 1996	A
5607188	Bahns et al.	Mar 1997	A
5610287	Nikiforov	Mar 1997	A
5620853	Smethers	Apr 1997	A
5621515	Hoshino	Apr 1997	A
5624850	Kumar et al.	Apr 1997	A
5625472	Mizrahi et al.	Apr 1997	A
5627040	Bierre et al.	May 1997	A
5627663	Horan et al.	May 1997	A
5633724	King et al.	May 1997	A
5633790	Gritter et al.	May 1997	A
5633975	Gary et al.	May 1997	A
5667976	Van Ness et al.	Sep 1997	A
5671308	Inoue et al.	Sep 1997	A
5682244	Barlow et al.	Oct 1997	A
5700037	Keller	Dec 1997	A
5712912	Tomko et al.	Jan 1998	A
5721435	Troll	Feb 1998	A
5729365	Sweatt	Mar 1998	A
5736330	Fulton	Apr 1998	A
5742432	Bianco	Apr 1998	A
5745615	Atkins et al.	Apr 1998	A
5745617	Starodubov et al.	Apr 1998	A
5759778	Li et al.	Jun 1998	A
5760961	Tompkin et al.	Jun 1998	A
5766956	Groger et al.	Jun 1998	A
5771251	Kringlebotn et al.	Jun 1998	A
5776694	Sheiness et al.	Jul 1998	A
5793502	Bianco et al.	Aug 1998	A
5798273	Shuler et al.	Aug 1998	A
5799231	Gates et al.	Aug 1998	A
5801857	Heckenkamp et al.	Sep 1998	A
5804384	Muller et al.	Sep 1998	A
5812272	King et al.	Sep 1998	A
5824472	Betlach et al.	Oct 1998	A
5824478	Muller	Oct 1998	A
5824557	Burke et al.	Oct 1998	A
5830622	Canning et al.	Nov 1998	A
5831698	Depp et al.	Nov 1998	A
5837475	Dorsal et al.	Nov 1998	A
5837552	Cotton	Nov 1998	A
5841555	Bianco et al.	Nov 1998	A
5846737	Kang	Dec 1998	A
5861113	Choquette et al.	Jan 1999	A
5874187	Colvin et al.	Feb 1999	A
5881197	Dong et al.	Mar 1999	A
5895750	Mushahwar et al.	Apr 1999	A
5922550	Everhart et al.	Jul 1999	A
5922617	Wang	Jul 1999	A
5925562	Nova et al.	Jul 1999	A
5925878	Challener	Jul 1999	A
5945679	Dorsel et al.	Aug 1999	A
5972542	Starodubov	Oct 1999	A
5976896	Kumar et al.	Nov 1999	A
5981166	Mandecki	Nov 1999	A
5986838	Thomas, III	Nov 1999	A
5989923	Lowe et al.	Nov 1999	A
5992742	Sullivan	Nov 1999	A
5998796	Liu et al.	Dec 1999	A
6001510	Meng et al.	Dec 1999	A
6005691	Grot et al.	Dec 1999	A
6017754	Chesnut et al.	Jan 2000	A
6025129	Nova et al.	Feb 2000	A
6025283	Roberts	Feb 2000	A
6027694	Boulton et al.	Feb 2000	A
6030581	Virtanen	Feb 2000	A
6035082	Murphy et al.	Mar 2000	A
6035083	Brennan et al.	Mar 2000	A
6036807	Brongers	Mar 2000	A
6043880	Andrews et al.	Mar 2000	A
6046925	Tsien et al.	Apr 2000	A
6049727	Crothall	Apr 2000	A
6057107	Fulton	May 2000	A
6060256	Everhart et al.	May 2000	A
6067167	Atkinson et al.	May 2000	A
6067392	Wakami et al.	May 2000	A
6078048	Stevens et al.	Jun 2000	A
6084995	Clements et al.	Jul 2000	A
6087186	Cargill et al.	Jul 2000	A
6088503	Chandler et al.	Jul 2000	A
6096496	Frankel et al.	Aug 2000	A
6096596	Gonzalez	Aug 2000	A
6097485	Lievan	Aug 2000	A
6103535	Pilevar et al.	Aug 2000	A
6118127	Liu et al.	Sep 2000	A
6128077	Jovin et al.	Oct 2000	A
6137931	Ishikawa et al.	Oct 2000	A
6143247	Sheppard, Jr. et al.	Nov 2000	A
6156501	McGall et al.	Dec 2000	A
6159748	Hechinger	Dec 2000	A
6160240	Momma et al.	Dec 2000	A
6160656	Mossberg et al.	Dec 2000	A
6164548	Curiel	Dec 2000	A
6165592	Berger et al.	Dec 2000	A
6165648	Colvin et al.	Dec 2000	A
6174648	Terao et al.	Jan 2001	B1
6194563	Cruickshank	Feb 2001	B1
6204068	Soini et al.	Mar 2001	B1
6204969	Jang	Mar 2001	B1
6214560	Yguerabide et al.	Apr 2001	B1
6218194	Lyndin et al.	Apr 2001	B1
6221579	Everhart et al.	Apr 2001	B1
6229635	Wulf	May 2001	B1
6229827	Fernald et al.	May 2001	B1
6229941	Yoon et al.	May 2001	B1
6242056	Spencer et al.	Jun 2001	B1
6259450	Chiabrera et al.	Jul 2001	B1
6262846	Nakai	Jul 2001	B1
6268128	Collins et al.	Jul 2001	B1
6277628	Johann et al.	Aug 2001	B1
6284437	Kashyap	Sep 2001	B1
6284459	Nova et al.	Sep 2001	B1
6285806	Kersey et al.	Sep 2001	B1
6288220	Kambara et al.	Sep 2001	B1
6292282	Mossberg et al.	Sep 2001	B1
6292319	Thomas, III	Sep 2001	B1
6301047	Hoshino et al.	Oct 2001	B1
6304263	Chiabrera et al.	Oct 2001	B1
6306587	Royer et al.	Oct 2001	B1
6309601	Juncosa et al.	Oct 2001	B1
6312961	Voirin et al.	Nov 2001	B1
6313771	Munroe et al.	Nov 2001	B1
6314220	Mossberg et al.	Nov 2001	B1
6319668	Nova et al.	Nov 2001	B1
6321007	Sanders	Nov 2001	B1
6322932	Colvin et al.	Nov 2001	B1
RE37473	Challener	Dec 2001	E
6328209	O'Boyle	Dec 2001	B1
6329963	Chiabrera et al.	Dec 2001	B1
6331273	Nova et al.	Dec 2001	B1
6335824	Overbeck	Jan 2002	B1
6340588	Nova et al.	Jan 2002	B1
6344298	Starodubov et al.	Feb 2002	B1
6352854	Nova et al.	Mar 2002	B1
6355198	Kim et al.	Mar 2002	B1
6355432	Fodor et al.	Mar 2002	B1
6356681	Chen et al.	Mar 2002	B1
6359734	Staub et al.	Mar 2002	B1
6361958	Shieh et al.	Mar 2002	B1
6363097	Linke et al.	Mar 2002	B1
6371370	Sadler et al.	Apr 2002	B2
6372428	Nova et al.	Apr 2002	B1
6383754	Kaufman et al.	May 2002	B1
6391562	Kambara et al.	May 2002	B2
6395558	Duveneck et al.	May 2002	B1
6399295	Kaylor et al.	Jun 2002	B1
6399935	Jovin et al.	Jun 2002	B1
6403320	Read et al.	Jun 2002	B1
6406841	Lee et al.	Jun 2002	B1
6406848	Bridgham et al.	Jun 2002	B1
6416714	Nova et al.	Jul 2002	B1
6416952	Pirrung et al.	Jul 2002	B1
6417010	Cargill et al.	Jul 2002	B1
6428707	Berg et al.	Aug 2002	B1
6428957	Delenstarr	Aug 2002	B1
6429022	Kunz et al.	Aug 2002	B1
6433849	Lowe	Aug 2002	B1
6436651	Everhart et al.	Aug 2002	B1
6440667	Fodor et al.	Aug 2002	B1
6456762	Nishiki et al.	Sep 2002	B1
RE37891	Collins et al.	Oct 2002	E
6462770	Cline et al.	Oct 2002	B1
6489606	Kersey et al.	Dec 2002	B1
6496287	Seiberle et al.	Dec 2002	B1
6506342	Frankel	Jan 2003	B1
6514767	Natan	Feb 2003	B1
6515753	Maher et al.	Feb 2003	B2
6522406	Rovira et al.	Feb 2003	B1
6524793	Chandler et al.	Feb 2003	B1
6533183	Aasmul et al.	Mar 2003	B2
6542673	Holter et al.	Apr 2003	B1
6544739	Fodor et al.	Apr 2003	B1
6545758	Sandstrom	Apr 2003	B1
6552809	Bergeron	Apr 2003	B1
6560017	Bianco	May 2003	B1
6565770	Mayer et al.	May 2003	B1
6573523	Long	Jun 2003	B1
6576424	Fodor et al.	Jun 2003	B2
6578712	Lawandy	Jun 2003	B2
6592036	Sadler et al.	Jul 2003	B2
6594421	Johnson et al.	Jul 2003	B1
6609728	Voerman et al.	Aug 2003	B1
6613581	Wada et al.	Sep 2003	B1
6618342	Johnson et al.	Sep 2003	B1
6622916	Bianco	Sep 2003	B1
6628439	Shiozawa et al.	Sep 2003	B2
6632655	Mehta et al.	Oct 2003	B1
6635470	Vann	Oct 2003	B1
6635863	Nihommori et al.	Oct 2003	B1
6646243	Pirrung et al.	Nov 2003	B2
6657758	Garner	Dec 2003	B1
6660147	Woudenberg et al.	Dec 2003	B1
6678429	Mossberg et al.	Jan 2004	B2
RE38430	Rosenstein	Feb 2004	E
6689316	Blyth et al.	Feb 2004	B1
6692031	McGrew	Feb 2004	B2
6692912	Boles et al.	Feb 2004	B1
6708618	Tsai	Mar 2004	B1
6750941	Satoh et al.	Jun 2004	B2
6794658	MacAulay	Sep 2004	B2
6806954	Sandstrom	Oct 2004	B2
6858184	Pelrine	Feb 2005	B2
6874639	Lawandy	Apr 2005	B2
6881789	Bosse	Apr 2005	B2
6892001	Ohta et al.	May 2005	B2
6905885	Colston et al.	Jun 2005	B2
6908737	Ravkin et al.	Jun 2005	B2
6919009	Stonas	Jul 2005	B2
6972883	Fujii et al.	Dec 2005	B2
6982996	Putnam et al.	Jan 2006	B1
7014815	Worthington et al.	Mar 2006	B1
7045049	Natan	May 2006	B1
7065032	Horimai	Jun 2006	B2
7080857	Patton	Jul 2006	B2
7092160	Putnam et al.	Aug 2006	B2
7106513	Moon et al.	Sep 2006	B2
7122384	Prober	Oct 2006	B2
7126755	Moon et al.	Oct 2006	B2
7164533	Moon	Jan 2007	B2
7190522	Moon	Mar 2007	B2
7215628	Horimai	May 2007	B2
7225082	Natan	May 2007	B1
7321541	Horimai	Jan 2008	B2
7339148	Kawano	Mar 2008	B2
7349158	Moon	Mar 2008	B2
7375890	Putnam et al.	May 2008	B2
7399643	Moon et al.	Jul 2008	B2
7433123	Putnam et al.	Oct 2008	B2
7441703	Moon	Oct 2008	B2
7508608	Kersey	Mar 2009	B2
7602952	Kersey	Oct 2009	B2
7604173	Kersey	Oct 2009	B2
7619819	Moon	Nov 2009	B2
7791802	Putnam et al.	Sep 2010	B2
7796333	Kersey et al.	Sep 2010	B2
20010007775	Seul et al.	Jul 2001	A1
20010020375	Novak et al.	Sep 2001	A1
20010029049	Walt	Oct 2001	A1
20020000471	Aasmul et al.	Jan 2002	A1
20020006664	Sabatini	Jan 2002	A1
20020018430	Heckenkamp et al.	Feb 2002	A1
20020022273	Empedocles et al.	Feb 2002	A1
20020025534	Goh et al.	Feb 2002	A1
20020031783	Empedocles et al.	Mar 2002	A1
20020034747	Bruchez et al.	Mar 2002	A1
20020039728	Kain	Apr 2002	A1
20020039732	Bruchez et al.	Apr 2002	A1
20020074513	Abel et al.	Jun 2002	A1
20020084329	Kaye	Jul 2002	A1
20020090650	Empedocles et al.	Jul 2002	A1
20020094528	Salafsky	Jul 2002	A1
20020097658	Worthington	Jul 2002	A1
20020155490	Skinner et al.	Oct 2002	A1
20020174918	Fujimura et al.	Nov 2002	A1
20020197456	Pope	Dec 2002	A1
20030008323	Ravkin et al.	Jan 2003	A1
20030021003	Ono et al.	Jan 2003	A1
20030032203	Sabatini et al.	Feb 2003	A1
20030077038	Murashima et al.	Apr 2003	A1
20030082568	Phan et al.	May 2003	A1
20030082587	Seul et al.	May 2003	A1
20030129654	Ravkin et al.	Jul 2003	A1
20030138208	Pawlak et al.	Jul 2003	A1
20030142704	Lawandy	Jul 2003	A1
20030142713	Lawandy	Jul 2003	A1
20030153006	Washizu	Aug 2003	A1
20030162296	Lawandy	Aug 2003	A1
20030184730	Price	Oct 2003	A1
20030203390	Kaye	Oct 2003	A1
20030228610	Seul	Dec 2003	A1
20040027968	Horimai	Feb 2004	A1
20040047030	MacAulay	Mar 2004	A1
20040062178	Horimai	Apr 2004	A1
20040075907	Moon et al.	Apr 2004	A1
20040100636	Somekh et al.	May 2004	A1
20040100892	Horimai	May 2004	A1
20040125370	Montagu	Jul 2004	A1
20040125424	Moon	Jul 2004	A1
20040126875	Putnam	Jul 2004	A1
20040132205	Moon et al.	Jul 2004	A1
20040156471	Sakata	Aug 2004	A1
20040170356	Iazikov et al.	Sep 2004	A1
20040175842	Roitman	Sep 2004	A1
20040209376	Natan et al.	Oct 2004	A1
20040233485	Moon	Nov 2004	A1
20040263923	Moon et al.	Dec 2004	A1
20050042764	Sailor et al.	Feb 2005	A1
20050056587	Allen	Mar 2005	A1
20050220408	Putnam	Oct 2005	A1
20050227252	Moon et al.	Oct 2005	A1
20050270603	Putnam et al.	Dec 2005	A1
20060023310	Putnam et al.	Feb 2006	A1
20060028727	Moon et al.	Feb 2006	A1
20060050544	Horimai	Mar 2006	A1
20060057729	Moon et al.	Mar 2006	A1
20060063271	Putnam et al.	Mar 2006	A1
20060067179	Matsumoto	Mar 2006	A1
20060071075	Moon et al.	Apr 2006	A1
20060072177	Putnam et al.	Apr 2006	A1
20060118630	Kersey et al.	Jun 2006	A1
20060119913	Moon	Jun 2006	A1
20060132877	Kersey	Jun 2006	A1
20060134324	Putnam et al.	Jun 2006	A1
20060139635	Kersey et al.	Jun 2006	A1
20060140074	Horimai	Jun 2006	A1
20060160208	Putnam et al.	Jul 2006	A1
20070121181	Moon et al.	May 2007	A1
20070236789	Moon	Oct 2007	A1
20080085565	Moon	Apr 2008	A1
20080129990	Moon	Jun 2008	A1
20080165656	Moon et al.	Jul 2008	A1
20080170664	Kalman	Jul 2008	A1
20080192311	Horimai	Aug 2008	A1
20090034078	Putnam	Feb 2009	A1
20090040885	Horimai	Feb 2009	A1
20090073520	Kersey	Mar 2009	A1
20090194589	Moon et al.	Aug 2009	A1
20100025482	Moon	Feb 2010	A1
20100072278	Putnam	Mar 2010	A1
20100099574	Moon	Apr 2010	A1

Foreign Referenced Citations (100)

Number	Date	Country
598661	May 1978	CH
598661	May 1978	CH
2416652	Oct 1975	DE
0 395 300	Oct 1990	EP
0 723 149	Jul 1996	EP
0 798 573	Oct 1997	EP
0 911 667	Apr 1999	EP
0 916 981	May 1999	EP
916981	May 1999	EP
0 972 817	Jan 2000	EP
1 182 054	Feb 2002	EP
1182054	Feb 2002	EP
1219979	Jul 2002	EP
2 118 189	Oct 1983	GB
2 129 551	May 1984	GB
2129551	May 1984	GB
2 138 821	Oct 1984	GB
2 299 235	Sep 1996	GB
2 306 484	May 1997	GB
2 319 838	Jun 1998	GB
2372100	Aug 2002	GB
58143254	Aug 1983	JP
01047950	Feb 1989	JP
05307119	Nov 1993	JP
06333102	Feb 1994	JP
08102544	Apr 1996	JP
08272923	Oct 1996	JP
10160705	Jun 1998	JP
11119029	Apr 1999	JP
2000-035521	Feb 2000	JP
20035521	Feb 2000	JP
2000249706	Sep 2000	JP
2002513166	May 2002	JP
2002182022	Jun 2002	JP
2003004671	Aug 2003	JP
WO 9106496	May 1991	WO
WO 9309668	May 1993	WO
WO 9428119	Dec 1994	WO
WO 9624061	Aug 1996	WO
WO 9636436	Nov 1996	WO
WO9636436	Nov 1996	WO
WO 9712680	Apr 1997	WO
WO 9715690	May 1997	WO
WO 9717258	May 1997	WO
WO 9731282	Aug 1997	WO
WO 9734171	Sep 1997	WO
WO 9804740	Feb 1998	WO
WO 9824549	Jun 1998	WO
WO 9902266	Jan 1999	WO
WO 9909042	Feb 1999	WO
WO 9932654	Jul 1999	WO
WO 9942209	Aug 1999	WO
WO 0008443	Feb 2000	WO
WO 0016893	Mar 2000	WO
WO0016893	Mar 2000	WO
WO 0019262	Jun 2000	WO
WO 0037914	Jun 2000	WO
WO 0037969	Jun 2000	WO
WO 0039617	Jul 2000	WO
WO 0061198	Oct 2000	WO
WO 0063419	Oct 2000	WO
WO0061198	Oct 2000	WO
WO 0158583	Aug 2001	WO
WO0158583	Aug 2001	WO
WO 0171322	Sep 2001	WO
WO0171322	Sep 2001	WO
WO 0178889	Oct 2001	WO
WO0178889	Oct 2001	WO
WO 0190225	Nov 2001	WO
WO 02059306	Aug 2002	WO
WO 02059603	Aug 2002	WO
WO02059306	Aug 2002	WO
WO 02064829	Aug 2002	WO
WO 03061983	Jul 2003	WO
WO03061983	Jul 2003	WO
WO 03091731	Nov 2003	WO
WO 2004011940	Feb 2004	WO
WO 2004015418	Feb 2004	WO
WO 2004019276	Mar 2004	WO
WO 2004024328	Mar 2004	WO
WO 2004025561	Mar 2004	WO
WO 2004025562	Mar 2004	WO
WO 2004025563	Mar 2004	WO
WO2004019276	Mar 2004	WO
WO2004024328	Mar 2004	WO
WO2004025562	Mar 2004	WO
WO 2004034012	Apr 2004	WO
WO 2004046697	Jun 2004	WO
WO 2004066210	Aug 2004	WO
WO2004066210	Aug 2004	WO
WO 2005026729	Mar 2005	WO
WO 2005027031	Mar 2005	WO
WO 2005029047	Mar 2005	WO
WO 2005033681	Apr 2005	WO
WO 2005050207	Jun 2005	WO
WO 2005079544	Sep 2005	WO
WO 2006020363	Feb 2006	WO
WO 2006055735	May 2006	WO
WO 2006055736	May 2006	WO
WO 2006076053	Jul 2006	WO

Related Publications (1)

	Number	Date	Country
	20080165656 A1	Jul 2008	US

Continuations (1)

	Number	Date	Country
Parent	10661116	Sep 2003	US
Child	12053242		US

Methods and systems for writing an optical code within or on a fiber substrate

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