Patent Application
20190064450
The present disclosure relates to integrated photonics, and in particular relates to methods of forming glass-based ferrules and glass-based coupling apparatus.
Photonic systems are presently used in a variety of applications and devices to communicate information using light (optical) signals. Photonic systems may include photonic integrated circuits (PICs), which are analogous to electronic integrated circuits in that they integrate multiple components into a single material where those components operate using light only or a combination of light and electricity. A typical PIC has a combination of electrical and optical functionality, and can include light transmitters (light sources) and light receivers (photodetectors), as well as electrical wiring and like components that serve to generate and carry electrical signals for conversion to optical signals and vice versa.
A PIC includes one or more optical waveguides that carry light in analogy to the way metal wires carry electricity in electronic integrated circuits. Just as the electricity traveling in the wires of an electronic integrated circuit carries electrical signals, the light traveling in the waveguides of a PIC carries optical signals.
To transmit the optical signals from the PIC to a remote device, the optical signals carried by a waveguide in the PIC need to be transferred or “optically coupled” to a corresponding optical fiber connected to the remote device. This optical coupling should have a suitable optical efficiency and the optical coupling apparatus should have a compact footprint, as well as being low-cost and able to be reliably connected and disconnected. In addition, the optical coupling should optically efficient even at relatively high operating temperatures since the PICs may generate significant amounts of heat. These relatively high operating temperatures may result in thermal expansion due to differences in the coefficients of thermal expansion (CTE) of the various components of the optical interface device and can adversely impact the optical coupling efficiency.
An aspect of the disclosure is a method of forming a ferrule or a coupling apparatus. The method includes: drawing a glass preform to form a drawn glass preform section with a size reduction, wherein the glass preform has a first longitudinal alignment feature; dividing the drawn glass preform section into at least first and second alignment members, with each alignment member having a length L that is in the range from 2 mm to 12 mm; and attaching the first and second alignment members in a spaced apart configuration to an upper surface of either: i) a glass support substrate to form the ferrule or ii) a PIC to form the coupling apparatus.
Another aspect of the disclosure includes a method of forming glass-based ferrules for a ferrule assembly. The method includes: drawing a glass preform to form a drawn glass preform section with a size reduction, wherein the glass preform has a first longitudinal alignment feature, and wherein the drawn pre-form section has a second longitudinal alignment feature defined by the first longitudinal alignment feature; dividing the drawn glass preform section into a plurality of canes; securing the plurality of canes on an upper surface of a glass support sheet to define a fabrication structure, wherein the canes are arranged in spaced-apart pairs; and dicing the fabrication structure including the plurality of canes and the glass support sheet to form a plurality of the ferrules, with each ferrule having a pair of spaced apart glass alignment members defined by the diced canes and supported by a glass support substrate defined by the diced glass support sheet.
Another aspect of the disclosure includes a method of forming an alignment member for a ferrule or a coupling apparatus. The method includes: forming a monolithic body with a central body axis, a length and a longitudinal central aperture in the form of a cross defined by first and second orthogonal sections having respective first and second central axes orthogonal to and that intersect at the central body axis, wherein the first and second orthogonal sections define four quadrants of the monolithic body, with each quadrant including a longitudinal bore that runs down the length of the monolithic body and offset from the central body axis; separating the monolithic body into the four quadrants, with each quadrant defining an alignment sub-structure; and cross-sectionally cutting at least one of the alignment sub-structures to form at least one alignment member.
Another aspect of the disclosure is a method of forming an alignment member that is “dual use,” i.e., that can be used for both a ferrule assembly that has a glass support substrate that supports optical fibers and a coupling apparatus for a PIC assembly that has a PIC that supports optical waveguides. The method includes: drawing a glass preform to form a drawn glass preform section with a size reduction, wherein the glass preform has a longitudinal alignment feature and a rectangular cross-sectional shape with first and second adjacent sides; dividing the drawn glass preform section into a plurality of alignment members, with each alignment member having a length L that is in the range from 2 mm to 12 mm; and wherein the optical waveguides and optical fibers define a relative alignment offset Δz, and wherein the longitudinal alignment feature resides at a first distance H1 from the first side and a second distance H2 from the second side, and wherein H1>H2 and wherein Δz is substantially equal to H1−H2.
Additional features and advantages are set forth in the Detailed Description that follows, and in part will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings. It is to be understood that both the foregoing general description and the following Detailed Description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.
The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments, and together with the Detailed Description serve to explain principles and operation of the various embodiments. As such, the disclosure will become more fully understood from the following Detailed Description, taken in conjunction with the accompanying Figures, in which:
Reference is now made in detail to various embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same or like reference numbers and symbols are used throughout the drawings to refer to the same or like parts. The drawings are not necessarily to scale, and one skilled in the art will recognize where the drawings have been simplified to illustrate the key aspects of the disclosure.
The claims as set forth below are incorporated into and constitute part of this Detailed Description.
Cartesian coordinates are shown in some of the Figures for the sake of reference and are not intended to be limiting as to direction or orientation.
Examples of glass-based ferrules and ferrule assemblies, glass-based coupling sub-assemblies and glass-based optical interface devices are described in the aforementioned patent application, entitled “Glass-based ferrule assemblies PIC assemblies and coupling sub-assemblies for optical interface devices for photonic systems,” which as noted above is incorporated by reference herein in its entirety.
Photonic System and PIC Assembly
The coupling apparatus 40 is configured to operably couple to ferrule assembly 100 via respective alignment members 42 so that the ferrule assembly is in optical communication with PIC assembly 20 of integrated photonic assembly 10 when mated. The combination of PIC assembly 20 and ferrule assembly 100 define an optical interface device 200, which is shown as being disconnected in
PIC Assembly and Coupling Apparatus
The PIC 21 can also include other components that are not shown, such as photoemitters, photodetectors, metal wiring, optical redirecting elements, electrical processing circuitry, optical processing circuitry, contact pads, etc., as is known in the art. In an example, PIC 21 is formed mainly from silicon (i.e., is silicon-based) and constitutes a silicon photonics (SiP) device. In another example, PIC 21 is formed mainly from glass, (i.e., is glass-based) and constitutes a passive planar lightwave circuit.
PIC assembly 20 includes coupling apparatus 40, which is configured to allow for the alignment of the optical coupling of the PIC assembly with ferrule 100. The coupling apparatus 40 as described below is shown in the form of a receptacle having guide holes 44 configured to receive respective alignment pins 46 from ferrule assembly 100, as shown in
The coupling apparatus 40 is disposed on upper surface 22 of PIC 21 and includes two spaced apart alignment members 42 (denoted 42A and 42B), and which are configured to respectively receive alignment pins 46 (denoted 46A and 46B; see
In an example, alignment members 42A and 42B reside outside of center portion 34 where array 30 of waveguides 32 resides. In an example, alignment members 42A and 42B are attached (fixed) to upper surface 22 of PIC 21 using a suitable method for the materials of the PIC 21 and the alignment members 42A,42B. By way of explanation, alignment members 42A,42B may be attached to PIC 21 using an adhesive, such as an epoxy (e.g., a UV-cured epoxy). In another example, if alignment members 42A and 42B are glass-based they may be attached (fixed) to PIC 21 using a thin absorbing film or a thin film of low melting glass or a glass frit or by using direct glass bonding techniques known in the art. Example methods of forming alignment members 42A and 42B are described below.
Coupling apparatus 40 comprises alignment members 42A and 42B and a PIC coupling assembly comprises PIC 21 with a coupling apparatus 40 (comprising alignment members 42A and 42B) attached thereto. The coupling apparatus 40 provides a precision alignment registration to the optical waveguides 32 of PIC 21 with another device such as ferrule assembly 100 or the like. Consequently, it is advantageous to have a coupling assembly that allows a precise and repeatable method of manufacture for placing and securing the coupling apparatus 40 to PIC 21 relative to the optical waveguides 32.
The coupling apparatus 40 as disclosed herein is either glass-based, i.e., at least a portion of the coupling apparatus is made of at least one type of glass, polymer-based, i.e., a portion of the coupling apparatus is made of at least one type of polymer, or a combination of glass and polymer as part of a “hybrid” configuration. For example, alignment members 42A and 42B can be made of a polymer while the other components such as the spacer member 162 as is
In another example hybrid configuration, alignment members 42A and 42B can be made of a polymer or glass with no other components used in the coupling apparatus. In an example, coupling apparatus is made of a single type of glass, i.e., all of the components of the coupling apparatus are made of the same glass material. In another example, the coupling apparatus 40 is made entirely of glass, but at least some of the components are made of different glass materials—for example, the alignment members 42A and 42B are made of a first glass material while all of the other components are made of a second glass material.
Alignment Members
Alignment members may have any suitable cross-sectional shape or size. In an example, guide hole 44 has a circular cross-sectional shape (x-z plane) to closely accommodate alignment pins 46 that in an example also has a circular cross-sectional shape. Other cross-sectional shapes can be used for guide hole 44 consistent with the cross-sectional shape of alignment pin 46. Also in an example, alignment member 42 has a substantially rectangular (x-z plane) cross-sectional shape of dimensions h and w, and further in an example has a substantially square cross-sectional shape, i.e., h=w. In one example, the cross-sectional shape of alignment member 42 has an aspect ratio h:w of no greater than 1:5 or 5:1, while in another example, the aspect ratio is no greater than 1:2 or 2:1. In another example, the aspect ratio h:w is substantially 1:1. In an example, the edges of alignment member 42 need not be perfectly square, e.g., they can be rounded.
In one example, alignment members 42A and 42B are made a molded polymer (e.g., polyphenylene sulfide or PPS), while in another example the alignment members are made of glass, such as silica, PYREX® glass, or a chemically strengthened glass. One example of chemically strengthened glass is GORILLA® glass, available from Corning, Inc., Corning, N.Y. Other chemically strengthened glasses can also be effectively employed.
In an example, dimensions h and w are in the range from 350 microns (0.35 mm) to 1500 microns (1.5 mm). In an example, h=w to within manufacturing tolerances. In an example, h and w have dimensions in the range from 500 microns to 800 microns, e.g., for small coupling sub-assemblies and small ferrules (e.g., about half the size of a standard MT connector). In an example, h=w=625 microns. The alignment member 42 also has a length L, which in an example is in the range from 2 millimeters (mm) to 20 mm, or from 2 mm to 6 mm, with an exemplary length L being nominally 3 millimeters. In an example, the length L=LC=LF, where LC is the length of coupling apparatus 40 and LF is the length of ferrule 145. However, any suitable sizes may be used with the concepts disclosed.
Dimensions of Coupling Apparatus
With reference again to
The array 30 of waveguides 32 also has a width WG. By way of example, an array 30 of n=12 optical waveguides with a pitch p=127 microns is WG=(n)(p)=(12)×(127)=1524 microns. Other suitable values for the pitch p can be used, e.g., 125 microns or 250 microns, and in an example the number n of waveguides 32 can be from n=2 to n=24, but other suitable values are possible. In an example, PIC 21 has a thickness THC of between 300 and 1000 microns, with an exemplary thickness THC being nominally 750 microns. The coupling apparatus 40 also has a height HC=THC+h and a length LC (see
Thus, the overall dimensions of coupling apparatus are height HC, width WC and length LC. In an example, these dimensions can be about the same as that for a standard MT connector, e.g., HC×WC×LC=3 mm×7 mm×8 mm, or can be about half the size, e.g., 1.5 mm×3.5 mm×4 mm. In an example, the dimensions HC×WC×LC can in the range from 5 mm×15 mm×20 mm to 1 mm×3 mm×2 mm, but other dimensions are possible.
Example Ferrule Assemblies
In an example, support substrate 110 is in the form of a planar sheet and is made of any suitable material. By way of example, the support substrate 110 may be a glass, such as a fusion-drawn glass, which could be chemically strengthened glass. Another method for making support substrate 110 as a planar glass sheet is by floating molten glass on a bed of molten metal. Another method of making support substrate 110 as a planar glass sheet is by using a slot draw process where molten glass flows out of a slot at the bottom of a refractory furnace. Yet another method of making the support substrate 110 as a planar glass sheet is by rolling a slab a glass into its final thickness. Of these, fusion-drawn glass forming may be preferred in certain applications due to its flatness and precision. Although, the term “planar” is used, the support substrate 110 may include fiber alignment features such as v-grooves or other geometry for aligning and fixing the optical fibers in a desired spacing. For instance, the support substrate 110 may comprise fiber alignment features etched into the surface for seating and spacing the optical fibers.
The ferrule assembly 100 includes an array 130 of optical fibers 132 each having core 133a, a cladding 133b surrounding the core (see close-up inset in
Also in an example, optical fibers 132 are small-clad optical fibers, i.e., the cladding 133b of optical fiber 132 is substantially smaller than that of the cladding used in a conventional optical fiber. By way of explanation, a standard single mode optical fiber can have a core diameter of about 10 microns and a cladding diameter ranging from 50 microns up to 125 microns. An advantage of using small-clad optical fibers for optical fibers 132 is that the pitch p′ can be made smaller than for conventional optical fibers, and can be made as small as the diameter d′ of the optical fiber, where the diameter dF is defined by the diameter of cladding 133b. Thus, small-clad optical fibers 132 can be more densely packed in ferrule assembly 100 while also affording greater latitude in matching the period p′ of the optical fibers to the period p of waveguides 32 of PIC assembly 20. Although ferrule assembly 100 is depicted with a single-row of optical fibers, the ferrule assembly 100 may have multiple rows of optical fibers to mate with a suitable PIC coupling assembly.
The ferrule assembly 100 also includes first and second spaced apart alignment members 42, denoted 42A and 42B, and as described above in connection with coupling apparatus 40. In an example, guide holes 44A and 44B respectively support alignment pins 46A and 46B. As discussed above, alignment pins 46A and 46B are configured to be received by respective guide holes 44A and 44B of alignment members 42A and 42B of coupling apparatus 40 so that ferrule assembly 100 can be aligned and mate to the coupling apparatus. The coupling results in the optical connection of optical interface device 200, with optical fibers 132 of the ferrule assembly being axially aligned with corresponding waveguides 32 of PIC 21 of PIC assembly 20. In an example, alignment pins 46A and 46B are made of a metal. The alignment members 42A and 42B reside on upper surface 122 of support substrate 100 adjacent respective sides 128A and 128B.
In an example, alignment members 42A and 42B are fixed to upper surface 122 using an adhesive, such as an epoxy (e.g., a UV-cured epoxy). In another example, alignment members 42A and 42B are fixed to upper surface 112 using a thin absorbing film or a thin film of low melting glass or glass frit or direct glass bonding techniques known in the art. The alignment members 42 and support substrate 110 define a ferrule body (“ferrule”) 145. In an example, alignment members 42A and 42B reside outside of center portion 126 where array 130 of waveguides 32 resides.
The array 130 of optical fibers 132 of ferrule assembly 100 is configured to optical couple to array 30 of waveguides 32 when ferrule assembly 100 is operably coupled to coupling apparatus 40 of PIC assembly 20. Thus, in an example, the optical fiber pitch p′ is equal to the waveguide pitch p, and the number n′ of optical fibers 132 is equal to the number n of waveguides 32.
In an example, ferrule assembly 100 includes a securing member 160 that has an upper surface 162 and a lower surface 164. The securing member 160 resides atop optical fiber array 130 with lower surface 164 in contact with optical fibers 132 to keep the optical fibers in place on upper surface 112 of support substrate 110, as shown in
Securing member 160 may be used as a jig to ensure the proper spacing and placement of alignment members 42A and 42B. The securing member 160 can also be used as a temporary fixture to insure proper placement and permanent fixing of optical fibers 132. In another example, the securing member 160 can be used as a permanent fixture to optical fiber array 130 and/or to alignment members 42A and 42B using adhesive, such as an epoxy (e.g., a UV-cured epoxy). In another example, securing member 160 can be fixed to alignment members 42A and 42B and/or to optical fiber array 130 using a thin absorbing film or a thin film of low melting glass or glass frit or direct glass bonding techniques known in the art.
In an example, support substrate 110 is made of black glass, a glass doped with metal such as iron or titanium, which can facilitate the use of a glass fusion process in assembling ferrule assembly 100. In an example, support substrate 100 can have a layer of glass that has a relatively low melting temperature (i.e., “low-melt glass”), e.g., of about 300 C. This can enable the use of bonding in an oven or other low-temperature non-localized heat source rather than using a laser or other relatively high-temperature and localized heating means.
Ferrule assembly 100 as disclosed herein is also glass-based or a combination of glass and polymer as part of a “hybrid” configuration, i.e., at least a portion of the coupling apparatus is made of at least one type of glass.
In an example, the support substrate 110, alignment members 42A and 42B and the optional securing member 160 of ferrule assembly 40 can be made of glass only, while in another example can be made with only some of the components being glass as part of a “hybrid” configuration. For example, support substrate 110 can be made of glass while alignment members 42A and 42B can be made of a polymer (i.e., a so-called “hybrid” configuration). In an example, ferrule 145 is made of a single type of glass, i.e., the same glass material. In another example, ferrule 145 is made entirely of glass, but at least some portions of the ferrule are made of different glass materials—for example, support substrate 110 is made of a first glass material while the two alignment members 42A and 42B are made of a second glass material. For instance, the first glass material may be may glass sheet made using a fusion glass process with a first glass material and the alignment members are made using a draw glass process with a second glass material.
Thus, in an example, optical interface device 200 has a hybrid construction wherein at least a portion of the optical interface device is made of glass since the ferrule assembly 100 and coupling apparatus 40 are each glass-based, as described above.
Dimensions of Ferrule Assembly
With reference to
Ferrule assembly 100 can be made to have a size that is substantially the same as a coupling apparatus 40, i.e., it can have a size of a standard MT ferrule and can be as small as about half the size of a standard MT ferrule. Thus, in an example, the dimensions HF×WF×LF can be in the range from 3 mm×7 mm×8 mm to 1.5 mm×3.5 mm×4 mm.
Method of Forming Alignment Members
Methods of forming alignment members 42 for use in forming coupling apparatus and ferrule 145 of ferrule assembly 100 are now discussed.
As discussed above, alignment member 42 has height and width dimensions h and w that may be any suitable values. In an example, the height and width dimensions h and w may be in the range from 1.5 millimeters to 350 microns (0.350 mm) and define an aspect ratio (h;w) of no greater than either 1:5 or 5:1, or no greater than 1:2 or 2:1. Likewise, as discussed above, an exemplary length L of alignment member 42 is 3 millimeters. The alignment member 42 is thus a relative small part that can be difficult to manufacture with precision.
In an example, alignment member 42 is formed using a drawing process such as used to form optical fibers.
There are multiple methods known in the art to create a desired glass preform 330. In one example, a thick-walled tube has its outer surface mechanically machined. In another example, soot can be pressed onto a central rod to form a monolithic body and then the soot machined before the body is consolidated into glass. Another method is by an extrusion process. Thus, glass preform 330 can be formed by at least of one the following processes: mechanical grinding, polishing, extrusion, soot pressing, consolidation, soot pressing, and machining.
An example glass preform 330 is rectangular and has cross-sectional width and height dimensions of hP and wP (see close-up inset I1), which defines an aspect ratio hP:wP. The preform 330 also has a central axis AP and longitudinal bore or hole 334 of diameter DP. The longitudinal bore or hole 334 need not be centered on central axis AP. Preforms of other shapes can also be used, e.g., generally circular, oval, etc., with a flat portion for mounting to a planar surface.
The preform 330 is arranged adjacent input end 312 of cylindrical heater 310 and then inserted through interior 316. The heat 318 heats preform 330, which is subjected to an axial tension T. The heat 318 softens the portion of preform 330 within interior 316 by bring heated portion of the preform to its melting temperature. The axial tension T causes preform 330 to be drawn down into a drawn preform section 350, which has substantially the same aspect ratio of the preform. The cross-sectional size reduction from preform 330 to drawn preform section 350 can be from 10× to 400×, with 50× being an exemplary size reduction.
Thus, for forming alignment member 42 to have desired height and width dimensions h and w, the preform height and width dimensions hP and wP can be from 10× to 400× as large. In a specific example, for desired height and width dimensions of h=w=625 microns and for a drawing process with a 50× size reduction, the preform height and width dimensions hP and wP can both be 31.25 mm.
The drawing process can be carried out to micron-sized tolerances, so that desired alignment member dimensions, which are typically measured in the many hundreds of microns, can be fabricated to relatively high tolerances, i.e., small percentage of the width w and height h (e.g., to 1% or 0.05% or 0.02% or even 0.01%).
The cuts can be made using, for example light-based means, e.g., a cutting laser beam 420, or mechanical means, such as a saw (e.g., a diamond-bladed saw) 424.
In an example, an alignment fixture 450 facilitates the alignment and spacing of canes 400 on fabrication structure 550.
The arrangement of canes 400 of
Once canes 400 are properly positioned on upper surface 512 of large support sheet 510, they are secured (attached) to the upper surface. In an example, the securing of canes 400 is accomplished using an adhesive, such as an epoxy (e.g., a UV-cured epoxy) or a thin absorbing film or a thin film of low melting glass or a glass frit or by using direct glass bonding techniques known in the art. The alignment fixtures 450 can then be removed from the front and back ends 402 and 404 of the pairs of canes 400. Many pairs of canes 400 can be aligned and secured in this manner, e.g., tens or hundreds, on a single large support sheet 510.
Once the pairs of canes 400 are secured in their aligned position on upper surface 512 of large support sheet 510, the resulting fabrication structure 550 is cut along the (x, y) cut lines 410 to define separate ferrules 145, as shown in
Unitary Structure for Forming Alignment Members
The monolithic body 600 has with a front end 602, a back end 604 and includes a central body axis AM that runs in the long direction (i.e., the y-direction). The monolithic body 600 also includes and a longitudinal central aperture 610 centered on the central axis AM. The central aperture 610 has cross shape with a two orthogonal sections, namely an x-section 611X that runs in the x-direction and a z-section 611Z that runs in the z-direction. Both the x-section 611X and the z-section 611Z also run the length of monolithic body, i.e., in the y-direction from front end 602 to back end 604. The x-section 611X has a central axis AX that runs in the x-direction and the z-section 611Z has a central axis AZ that runs in the z-direction. The central axes AX and AZ are thus orthogonal to central body axis AM and intersect at the central body axis. In an example, x-section 611X and z-section 611Z have the same size and shape, though generally they need not have the same size and shape.
The x-section 611X and the z-section 611z of cross-shaped central aperture 610 divides monolithic body 600 into four quadrants 612. Each quadrant 612 includes a longitudinal bore 614 that is offset from the central body axis AM. In an example, the longitudinal bore 614 can be centered in quadrant 612, but can also be off-centered as well. The monolithic body 600 has width wm, height hm and a length LM. When using extrusion to form monolithic body 600, the length LM can be very large as compared to the width w and height h, e.g., 0.5 meters or 1 meter. When using a molding or 3D printing process to form monolithic body 600, the length LM can substantially smaller, e.g., in the range of 3 mm to 50 mm. In an example, the width wm is about 2w (i.e., twice the width of alignment member 42) and the height hm is about 2h (i.e., twice the height of alignment member 42). Thus, in an example, the width wm and height hm are both in the range from about 700 microns to about 3000 microns.
In an example, monolithic body 600 has an outer cross-sectional shape that is substantially rectangular, and in an example is square. In other examples, monolithic body 600 can have an outer cross-sectional shape that is non-rectangular shape, e.g., substantially circular, polygonal, etc. In an example, the outer cross-sectional shape of monolithic body 600 can include rounded corners.
The precision formation of monolithic body 600 and the precise division of the monolithic body to form alignment sub-structures 650 results in the recessed surfaces 652S and 656S and corresponding lips 652L and 656L being useful as reference and/or alignment features for precise positioning and aligning alignment members 42 on upper surface 112 of support substrate 110. In an example, lips 656L of the two alignment sub-structures 650 can be formed so that they contact the upper surface of securing member 160 while the outside edges of the securing member contact the recessed surfaces 656S of the alignment sub-structures. Thus, recessed surfaces 652S and 656S of each alignment member 42 can each be used as a datum during the fabrication of ferrule 145 or coupling apparatus 40.
Dual-Use Alignment Member
When forming optical interface device 200, the waveguides 32 of PIC 21 need to be optically aligned with optical fibers 132 of ferrule assembly 100 when the alignment features of ferrule assembly and coupling apparatus operably engage. This is referred to as the fiber-to-waveguide alignment condition.
The two orientations of alignment member 42 in
In an example, alignment member 42 is configured for dual use, i.e., it can be used in either ferrule assembly 100 or coupling apparatus 40 even though the geometric requirements for meeting the fiber-to-waveguide alignment condition are different for ferrule assembly 100 versus coupling apparatus 40. For alignment member 42 to be dual use, the difference in the heights ΔH=H1−H2 is selected to be substantially the same as the fiber-waveguide offset Δz. Thus, alignment members 42 with the same cross-sectional geometry and with different heights H1 and H2 can be used for both ferrule 145 and coupling apparatus 40 simply by rotating the alignment members used to form the ferrule relative to orientation used in the coupling apparatus.
Note that the height h of the alignment members 42 used for coupling apparatus 40 is the width w of the alignment members used for ferrule assembly 100. Likewise, the width w of the alignment members 42 used for coupling apparatus 40 is the height h of the alignment members used for ferrule assembly 100.
Alignment member 42 can have a square cross-sectional shape (i.e., h=w), as long ΔH=Δz, which requires that H1 and H2 not be equal. It is also noted that the description of the “dual use” alignment member 42 set forth above can be made with reference to first to coupling assembly 40 and then to ferrule assembly 100 without loss of generality.
It will be apparent to those skilled in the art that various modifications to the preferred embodiments of the disclosure as described herein can be made without departing from the spirit or scope of the disclosure as defined in the appended claims. Thus, the disclosure covers the modifications and variations provided they come within the scope of the appended claims and the equivalents thereto.
This application is a continuation of International Application No. PCT/US17/29584, filed on Apr. 26, 2017, which claims the benefit of priority to U.S. Application Nos. 62/329,435 and 62/329,566, both filed on Apr. 29, 2016, the content of which is relied upon and incorporated herein by reference in entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62329435 | Apr 2016 | US | |
| 62329566 | Apr 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US17/29584 | Apr 2017 | US |
| Child | 16170199 | US |
