Patent Application
20190391345
The present invention relates to optical signal transmissions, in particular a device for routing optical data signals for use in an optical communications module.
Given the increasing bandwidth requirements for modern day data transmission (e.g., for high definition video data), fiber optic signal transmissions have become ubiquitous for communicating data. Optical signals are transmitted over optical fibers, through a network of optical fibers and associated connectors and switches. The optical fibers demonstrate a significantly higher bandwidth data transmission capacity and lower signal losses compared to copper wires for a given physical size/space.
In fiber optic signal transmission, conversions of optical signals and electrical signals take place beyond the terminating end of the optical fiber. Specifically, at the output end of an optical fiber, light from the optical fiber is detected by a transducing receiver and converted into an electrical signal for further data processing downstream (i.e., optical-to-electrical conversion). At the input end of the optical fiber, electrical signals are converted into light to be input into the optical fiber by a transducing transmitter (i.e., electrical-to-optical conversion).
To couple the input/output of the optical fiber to the transmitter/receiver, optical elements such as lenses are required to collimate and/or focus light from a light source (e.g., a laser) into the input end of the optical fiber, and to collimate and/or focus light from the output end of the optical fiber to a photo diode detector. To achieve acceptable signal levels, optical fibers must be precisely aligned at tight tolerance to the transmitters and receivers, so that the optical fibers are precisely aligned to the optical elements supported with respect to the transmitters and receivers.
In the past, given the internal optical elements and structures needed to achieve the required optical alignments, the transmitters and receivers are provided with coupling structures having connection ports to which optical fibers are coupled using connectors terminating the optical fibers. Given optical fibers are brittle, they must be handled with care during and after physical connection to the transmitter and receiver structures. The transmitters and receivers and associated structures having the connection ports are therefore generally bulky, which take up significant space, thereby making them not suitable for use in smaller electronic devices.
Heretofore, the coupling structure for optical fibers and transmitters and receivers are generally quite expensive and comparatively large in size for a given port count.
Referring to U.S. Patent Application Publication No. 2003/223131A1, one category of coupling devices is referred to in the art as an optical subassembly (OSA) for an optoelectronic module, which includes a lens and/or an optoelectronic device, e.g., having a laser (i.e., a transmitter optical subassembly or TOSA) or a photoelectric receiver chip (i.e., a receiver optical subassembly ROSA). The components of the OSA are mounted on a silicon optical bench.
Further referring to U.S. Pat. No. 6,869,231, the optical bench is essentially a mounting block, which includes a plurality of openings for accurately mounting the various components to obtain acceptable optical alignment of the components, e.g., including one or more ball lenses, a semiconductor laser chip (in the case of a TOSA) or a package photodiode receiver (in the case of a ROSA), and other components, such as optical isolator, etc. The semiconductor laser chip is used to generate light signals for optical communication over an optical fiber. The photodiode receiver is used to receive light signals communicated over an optical fiber. The ball lens is used to focus light signals between an optical fiber and the optical transmitter/receiver. Another ball lens collimates the light output from the semiconductor laser. In a further disclosed embodiment, an optical transceiver includes the optical bench on which a receiver and a transmitter are mounted.
U.S. Pat. No. 8,103,140 discloses a silicon substrate optical system, in which the optical bench includes a silicon substrate that is etched to receive optical components, including an input optical fiber, a pump source, a photodiode, an output optical fiber, and other optical components.
Heretofore, some OSA includes a turning mirror to redirect optical signal. U.S. Pat. No. 8,168,939 discloses an OSA in the form of a light source assembly that supports direct coupling to a photonically enabled complementary CMOS chip. The OSA disclosed therein includes a laser, a microlens and a turning mirror mounted on an optical bench. The optical signal is reflected at an angle defined by the turning mirror, and transmitted out of the light source assembly to one or more grating couplers in the chip. The turning mirror may be integrated in a lid affixed to the optical bench or be integrated in the optical bench.
Chen et al. discloses a miniaturized bidirectional OSA using a silicon optical bench having a 45-degree micro-reflector to direct light from optical fibers to a photodiode and light from a VSCEL (vertical-cavity surface-emitting laser) to optical fibers. (Optical Engineering, 51(11), 115005 (Nov. 1, 2012)).
The above noted OSA all use a substrate (in particular a silicon substrate) that is precision etched to form the features on the optical bench for accurately affixing various components such as at least one ball lens, laser diode, photodiode, etc, to obtain acceptable optical alignment. The turning mirrors are formed by etching crystalline surfaces to define the reflective surfaces, or as separate prisms bonded to the etched bench. Further, fiducials are etched on the substrates, which are relied upon for alignment of the silicon optical bench to external components.
While micro-machining by silicon etching is well developed, it nonetheless involves complex fabrication steps and challenges using silicon as the working material. For example, the turning mirror is limited to a flat surface defining a turning angle conforming to the angle of the crystalline surface plane. Turning mirrors defined by the flat silicon surface planes are less efficient in redirecting light, and cannot reshape light beam. Ball lenses are therefore required to reshape the light beams, but beam shaping is limited using a ball lens. Given the difficulty to assemble other types of lenses on the silicon optical bench, ball lenses, which are symmetrical in all axes, can be used on the silicon optical bench. The separate components (e.g., mirrors, lens, etc.) are required to be accurately aligned and affixed to the silicon optical bench at tight tolerances, which involve challenging manufacturing steps.
The above noted drawbacks of existing coupling devices for optical data transmission are exacerbated in multi-channel optical data transmissions. Optical alignment of various optical components must be with sub-micron precision. The optical bench for optical alignment of the laser diode or photodiode, the ball lens and the mirror, and the connection and optical alignment of the optical fibers with respect to the light source/sensors must be fabricated, and the various components assembled on the optical bench, with sub-micron precision. As if parts, namely optical benches, with such precision levels were not challenging enough, for the parts to be economical produced, it should be done in a fully automated, high-speed process.
What is needed is an improved structure for a coupling device for routing optical signals, which may include physically and optically coupling input/output of an optical fiber, which improves manufacturability, ease of use, functionality and reliability at reduced costs.
The present invention provides a coupling device (e.g., a stamped optic) for use in an optical communications module, which may include physically and optically coupling to an optical component, e.g., an input/output end of an optical fiber, for routing optical signals. The coupling device is implemented with a stamped reflective surface for routing/redirecting optical signals, and may include an integrated structure for physically and optically coupling an optical component, e.g., an optical fiber, to an optical receiver and/or transmitter, which improves manufacturability, ease of use and reliability at reduced costs, thereby overcomes many of the drawbacks of the prior art structures.
According to the present invention, the coupling device includes a stamped structured surface (e.g., a reflector) that functions as an optical element that directs light to/from another optical component, e.g., to/from the input/output ends of the optical fiber, by reflection (which may also include deflection and diffraction of incident light). The coupling device forms an optical bench for supporting the optical component, e.g., the optical fiber.
The structured reflective surface may be configured to be flat, concave or convex. In one embodiment, the structured reflective surface has a smooth surface with mirror finish. It may instead be a textured surface that is reflective. The structured reflective surface may have a uniform surface characteristic, or varying surface characteristics, such as varying degree of smoothness and/or textures, or a combination of various regions of smooth and textured surfaces making up the structured reflective surface. The structured reflective surface may have a surface profile and/or optical characteristic corresponding to at least one of the following equivalent optical element: mirror, focusing lens, diverging lens, diffraction grating, or a combination of the foregoing. The structured reflective surface may have more than one region corresponding to a different equivalent optical element (e.g., a central region that is focusing surrounded by an annular region that is diverging). Accordingly, depending on the geometry of the reflective surface, light can be redirected, and may further be reshaped, without requiring use of any lens (e.g., a ball lens). The structured reflective surface may thus be configured to, for example, collimate a diverging light beam into a collimated light beam and reflect the beam by a non-zero angle relative to an angle of incidence of the diverging light beam on the reflective surface. In one embodiment, the structured reflective surface is defined on an opaque material that does not transmit light through the surface.
In another aspect of the present invention, the coupling device also includes a structure for retaining an optical element, e.g., an optical fiber retention structure, which securely and accurately aligns the optical fiber with respect to the structured reflective surface. In one embodiment, the fiber retention structure includes at least one groove (or one or more grooves) that positively receives the optical fiber in a manner with the end of the optical fiber at a defined distance to and aligned with the structured reflective surface. The location and orientation of the structured reflective surface is fixed in relation to the fiber retention structure. In one embodiment, the fiber retention structure and the structured reflective surface are defined on the same (e.g., monolithic or unitary) structure of the coupling device. In an alternate embodiment, the fiber retention structure and the structure reflective surface are defined on separate structures that are coupled together to form the coupling device.
In one embodiment of the present invention, the structured reflective surface and fiber retention structure are defined by an open structure, which lends itself to mass production processes such as stamping, which are low cost, high throughput processes. In one embodiment, the structured reflective surface and the fiber retention grooves are formed by stamping a metal material. In one embodiment, the metal material may be chosen to have high stiffness (e.g., stainless steel), chemical inertness (e.g., titanium), high temperature stability (nickel alloy), low thermal expansion (e.g., Invar), or to match thermal expansion to other materials (e.g., Kovar for matching glass). Alternatively, the material may be a hard plastic or other hard polymeric material.
In one embodiment, the coupling device may be attached to an optical transmitter and/or receiver, with the structured reflective surface aligned to the light source (e.g., a laser) in the transmitter or to the detector (e.g., a photo diode) in the receiver. The transmitter/receiver may be hermetically sealed to the coupling device. The transmitter/receiver may be provided with conductive contact pads for electrical coupling to external circuitry. Given the fixed structured reflective surface and the fiber retention structure are precisely defined on the same coupling device, by aligning the light source in the transmitter or the light detector in the receiver to the structured reflective surface in the coupling device, the light source/detector would be precisely aligned to the input/output end of the optical fiber. In one embodiment, a method of precise alignment of the transmitter/receiver to the coupling device comprises superimposing complementary alignment marks provided on the transmitter/receiver and the coupling device.
In a further aspect of the present invention, silicon optical benches, such as those disclosed in the patents discussed in the Background section herein, can be replaced by a stamped optical bench.
In another aspect of the present invention, an optical fiber is structured as an active optical cable (AOC), which is a cable known in the art to have a transmitter at one terminal end of the optical fiber for electrical-to-optical conversion, and a receiver at another terminal end of the optical fiber for optical-to-electrical conversion.
The coupling device in accordance with the present invention overcomes many of the deficiencies of the prior art, which provides ease of use and high reliability with low environmental sensitivity, and which can be fabricated at low cost. The inventive coupling device may be configured for single or multiple channel optical data transmissions, e.g., to support a single or multiple fibers, for optical input, optical output or both (for bi-directional data communication).
In a further aspect of the present invention, silicon optical benches having particular defined optical paths through various optical elements and/or components can be replaced by a stamped optical bench in accordance with the present invention. Features and components defined on a silicon optical bench can be transformed to corresponding features defined on a stamped optical bench, and achieving a similar defined optical path with optical alignment at tight tolerances. Prior art silicon optical benches may be re-configured with stamped optical benches having similar defined optical paths. A stamped optical bench could have similar overall size and configuration, and similar footprint, compared to a corresponding silicon optical bench. The stamped optical bench would be backward compatible to replace a silicon optical bench in an optical subassembly. It is conceivable that stamped optical benches could be configured to have a smaller footprint and overall size than silicon optical benches. A stamped optical bench can effectively simplify the configuration of a silicon optical bench without compromising the desired defined optical path.
For a fuller understanding of the nature and advantages of the invention, as well as the preferred mode of use, reference should be made to the following detailed description read in conjunction with the accompanying drawings. In the following drawings, like reference numerals designate like or similar parts throughout the drawings.
This invention is described below in reference to various embodiments with reference to the figures. While this invention is described in terms of the best mode for achieving this invention's objectives, it will be appreciated by those skilled in the art that variations may be accomplished in view of these teachings without deviating from the spirit or scope of the invention.
The present invention provides a coupling device (e.g., a stamped optic), which may include physically and optically coupling an optical component, e.g., an input/output end of an optical fiber, for routing optical signals. The coupling device is implemented with a stamped reflective surface for routing/redirecting optical signals, and may include one or more attached or integrated structures for coupling (e.g., physically and/or optically coupling) an optical component, e.g., an optical fiber, to an optical receiver and/or transmitter, which improves manufacturability, ease of use and reliability at reduced costs, and thereby overcomes many of the drawbacks of the prior art structures.
According to the present invention, the coupling device includes a stamped structured surface on a base, which functions as an optical element that directs light to/from another optical component, e.g., to/from the input/output ends of the optical fiber, by reflection (which may also include deflection and diffraction of incident light). The coupling device forms an optical bench for supporting the optical component(s), e.g., the optical fiber. The stamped base is essentially a stamped optical bench on which optical element(s) (e.g., the structured reflective surface, and/or lenses such as ball lenses) and optical component(s) (e.g., optical fiber) are optically aligned with each other precisely. Such alignment is passive alignment, without requiring actively reading the optical signal transmitted through the components supported on the optical bench.
In
In the illustrated embodiment, the optical fiber may be a 50/125 graded index optical fiber, with a numerical aperture (NA) of 0.2+/−0.015. The structured reflective surfaces 12 and 14 are configured as concave mirrors, having an aperture width not exceeding 250 μm in order to match the standard pitch between two optical fibers in a ribbon cable. The optical axis of the concave mirrors are aligned with the axis of the optical fiber 10. The ends 17 and 19 (flat or angled-polished end faces) of the optical fibers are at an effective distance (along the optical axis) of about 0.245 mm from the respective structured reflective surfaces 12 and 14. The light source in the transmitter 16 and the optical detector in the receiver 18 are at an effective distance (along the optical axis) of about 0.1 mm from the respective structured reflective surfaces 12 and 14. The optical source may be a VCSEL, having 850 nm wavelength, 6 mW optical output power, and 20 to 30 degrees beam divergence. The optical detector may be a PIN photo diode with an active area of about 70 μm diameter.
According to one aspect of the present invention, the structured reflective surface may be formed by precision stamping a metal material.
Referring to
The groove 22 is structured to securely retain the fiber 10 (bare section with cladding exposed, without protective buffer and jacket layers) by clamping the fiber 10, e.g., by a mechanical or interference fit (or press fit). The interference fit assures that the fiber 10 is clamped in place and consequently the position and orientation of the fiber 10 is set by the location and longitudinal axis of the groove 22. In the illustrated embodiment, the groove 22 has a U-shaped cross-section that snuggly receive the bare optical fiber 10 (i.e., with the cladding exposed, without the buffer and protective layers). The sidewalls of the groove 22 are substantially parallel, wherein the opening of the groove may be slightly narrower than the parallel spacing between the sidewalls (i.e., with a slight C-shaped cross-section) to provide additional mechanical or interference fit for the fiber 10. Further details of the open groove structure can be found in copending U.S. patent application Ser. No. 13/440,970 filed on Apr. 5, 2012, which is fully incorporated by reference herein. The base 26 having the groove 22 is effectively a one-piece open ferrule supporting the optical fiber 10 in precise location and alignment with the structured reflective surface 13. The location of the structured reflective surface 13 is fixed with respect to the groove 22 and the shoulder 27, and hence fixed with respect to the end face of the optical fiber 10. The structured reflective surface 13 is not supported on a moving part and does not involve any moving part.
In one embodiment, the base 26 of the coupling device is formed of a metal material. In one embodiment, the metal material may be chosen to have high stiffness (e.g., stainless steel), chemical inertness (e.g., titanium), high temperature stability (nickel alloy), low thermal expansion (e.g., Invar), or to match thermal expansion to other materials (e.g., Kovar for matching glass). For reflectivity, the base 26 may be formed of a metal such as aluminum or copper, which offer higher optical reflectivity. The reflectivity can also be achieved by plating materials such as gold, silver, nickel, aluminum, etc. onto the body 26. Alternatively, the material may be a hard plastic or other hard polymeric material. The above disclosed open structure of the coupling device having the structured reflective surface and the fiber retention structure lends itself to mass production processes such as stamping, which are low cost, high throughput processes. A precision stamping process and apparatus has been disclosed in U.S. Pat. No. 7,343,770, which was commonly assigned to the assignee of the present invention. This patent is fully incorporated by reference as if fully set forth herein. The process and stamping apparatus disclosed therein may be adapted to precision stamping the base of the present invention.
In this embodiment, the base 46 has raised sidewalls 37 defining a cavity 36 in which the structured reflective surface 43 and grooves are located. The cavity 36 provides space for accommodating the height of the IC chip mounted on the circuit board 51. The height of the sidewalls 37 defines the distance between the light source/detector in the transmitter/receiver 38 and the structured reflective surface 43 in the coupling device 39. Referring also to
As one can appreciate, in the module 40, given the fixed structured reflective surface and the fiber retention structure are precisely defined on the same coupling device, by aligning the light source in the transmitter or the light detector in the receiver to the structured reflective surface in the coupling device, the light source/detector would be precisely aligned to the input/output end of the optical fiber.
From another perspective, the above described combination of transmitter/receiver and coupling device may be perceived to be an integrated transmitter/receiver module that includes a structured reflective surface and an integral coupling structure that aligns an optical fiber to the structured reflective surface.
The coupling device 39 may be stamped from a malleable metal material, as discussed earlier. The top surface 33 of the sidewalls 37 provides a bonding area for attaching to the transmitter/receiver 38. The transmitter/receiver 38 may be attached to the coupling device 39 by glue, epoxy, solder or welding. In one embodiment, the transmitter/receiver 38 may be hermetically sealed against the coupling device 39, for example, by laser welding, soldering, or blazing. The transmitter/receiver 38 and the coupling device can be manufactured and tested separately prior to assembly.
In another aspect of the present invention, an optical fiber is structured as an active optical cable (AOC), which is a cable known in the art to have a transmitter at one terminal end of the optical fiber for electrical-to-optical conversion, and a receiver at another terminal end of the optical fiber for optical-to-electrical conversion.
Referring also to the schematic drawing of
The coupling device in accordance with the present invention overcomes many of the deficiencies of the prior art, which provides ease of use and high reliability with low environmental sensitivity, and which can be fabricated at low cost. The inventive coupling device may be configured to support a single or multiple fibers, for optical input, optical output or both (for bi-direction data communication).
While the embodiments above are described in reference to a coupling device for a single optical fiber, it is well within the scope and spirit of the present invention to adapt the above disclosed coupling device structures for multiple optical fibers by providing parallel grooves in the coupling device, such as in the coupling device disclosed in parent U.S. patent application Ser. No. 13/861,273 filed on Apr. 11, 2013 (which had been incorporated by reference herein). It discloses a coupling device in the form of a hermetic optical fiber alignment assembly having integrated optical element. Referring to
For all the above described embodiments, from another perspective, the combination of transmitter/receiver and coupling device may be instead perceived to be an integrated transmitter/receiver module that includes one or more light sources/detectors, an integral coupling structure that includes one or more structured reflective surfaces and aligns one or more optical fibers to the structured reflective surfaces.
Further, in the above described embodiments, the optical fiber is an example of an optical component that can be supported by the base (more specifically retained in integrally formed stamped grooves in the base) in alignment with the stamped structured surface in the coupling device, and the structured reflective device is an example of a structured surface. The corresponding alignment structure on the base comprises features defining a groove that is integrally formed by with the structured reflective surface by stamping a metal stock material (e.g., in the form of a blank, or a strip). Other types of optical components, such as ball lenses, optoelectronic devices (e.g., a light source such as a VCSEL, a photosensor such as a photodiode), etc., can be supported in integrally stamped alignment structures, e.g., features such as grooves (including slots) for optically aligning optical fibers with the stamped structured reflective surface. Accordingly, the stamped base supports the inventive concept of a stamped optical bench on which optical element(s) (i.e., the structured reflective surface) and optical component(s) (e.g., optical fiber) are optically aligned with each other precisely. Such optical alignment involves passive alignment, without requiring actively reading an optical signal transmitted through the components supported on the optical bench.
In a further aspect of the present invention, silicon optical benches having particular defined optical paths through various optical elements and components, such as those disclosed in the patents discussed in the Background section herein, can be replaced by a stamped optical bench in accordance with the present invention. To illustrate the inventive concept,
Specifically,
In this embodiment, the passive alignment structures including features such as an axisymmetrical seat 134 for seating a ball lens 136 and a slot 135 for seating an optical component 137, such as an optoelectronic device (e.g., a light source, such as laser diode or a VSCEL and/or a light sensor, such as a photodiode), as shown in
The slot 135 has at least one step/shoulder 141 for referencing placement of the optical component 137 on the base 132. Another step/shoulder 131 may be provided to define a stop for abutting the end of the optical component 137, so as to define and/or limit the distance between the optical component 137 and the ball lens 136. One or more visual alignment marks (also known in the art as “fiducials” or “fiduciary marks”) are provided on the base 132, to provide an optical reference to facilitate accurately positioning the optical axis of the optical component 137 (e.g., the axis of the output light beam in the case of a light source such as a VSCEL, or the light receiving axis of the sensor in the case of the light sensor; see optical path 143 shown in
As shown in
Referring also to
For the optical bench illustrated in
As was in the case of the earlier described embodiments, the above described surface features of the base 132 are integrally stamped from the same metal stock material. Matching punches and dies having appropriate features defined thereon are applied in a series stamping operations to obtain the desired geometries of the above-described features of the optical bench 130. Preferably, at least the features critical to precise optical alignment are subject to a final stamping operation, by which such features are finally defined on the same (e.g., monolithic or unitary) base 132. For the illustrated embodiment, this would include at least the structured reflective surface 133, the seat 134 and the alignment marks 138, and further the gussets 139, the slot 135 (if the shoulders 131 and 141 are required for optical alignment), and the flat surface of the pad 142. These features may be individually preformed during a sequence of stamping operations, but they are subject to a final stamping operation using a stamping punch that integrally defines the final geometry of the combination of these features in relationship to each other on the same (monolithic or unitary) base 132. A final set of punch and die is applied to produce the desired final geometries that would define the optical path and optical alignment structures (e.g., features such as lens seat, registration shoulders, alignment marks) provided by the optical bench 130. This is akin to using the punch 200 in the earlier described embodiment of
For example, the following separate stamping operations may be applied to preform the following features in preparation for the final features: a through-hole is punch out from the metal stock material to prepare for forming the seat 134; a wall is preshaped from the metal stock material to prepare for the extended portion 140 and gussets 139; and a pilot slot is preformed to prepare for the slot 135. A subsequent single stamping operation forms the final geometries of the seat 134, slot 135, and the extended portion 140 and gussets 139.
The strip 152 has a series of indexing holes 151 formed along its opposing longitudinal edges, as shown in
As earlier noted in connection with the earlier embodiments, the precision stamping process and apparatus has disclosed in U.S. Pat. No. 7,343,770 (which was commonly assigned to the assignee of the present invention) could be adopted to stamp strip 152 to form the features of the coupling devices of the present invention (including the structured reflective surface and alignment structures having features discussed above). The stamping process and system can produce parts with a tolerance of at least 1000 nm (i.e., a tolerance of 1000 nm or less/better). This patent is fully incorporated by reference as if fully set forth herein.
Arrow A represents the direction of feed of the strip 152. Section 154a represents a “finished” stamped section at which the features of the coupling devices 130 have been finally formed by stamping. Given the direction of feed (arrow A), the sections 154b are also “finished” stamped sections that were subject to earlier stamping operations. Sections 154c are sections to be finally stamped to finish forming the coupling devices 130.
As shown in
Based on prior experimental results, it has been found that stamped structured reflective surfaces can achieve a peak-to-valley form error of less than 1 μm over a 1 mm diameter area. Surface roughness (Ra) based on scanning white light interferometry is on the order of 8 nm or better. The compression of the malleable material between the punch and die generates high contact pressure for a high reflective, mirror-quality surface.
It is noted that the optical benches 130 are separated (e.g., by cutting along dotted lines 153) from the regions 155 in strip 152, which may be subject to further processing (e.g., surface finishing and/or coating, such as gold plating to improve reflectivity, anti-corrosion, etc.) Alternatively, the optical benches 130 may be subject to further processing prior to separating from the strip 152. Further, the ball lens 136 and other optical components may be mounted while the optical benches 130 are still attached to strip or after cutting from the strip 152.
The above-described embodiment is illustrative of how a basic combination of features and components (i.e., a ball lens, a mirror, an optoelectronic device (e.g., a light source and/or sensor) defined on a silicon optical bench can be transformed to corresponding features defined on a stamped optical bench, achieving a similar defined optical path with optical alignment at tight tolerances. Other configurations of prior art silicon optical benches may be re-configured with stamped optical benches having similar defined optical paths. A stamped optical bench could have similar overall size and configuration, and similar footprint, compared to a corresponding silicon optical bench. The stamped optical bench would be backward compatible to replace a silicon optical bench. It is conceivable that stamped optical benches could be configured to have a smaller footprint and overall size than silicon optical benches.
A stamped optical bench can effectively simplify the configuration of a silicon optical bench, without compromising the desired defined optical path. Depending on the geometry of the structured reflective surface, light can be redirected, and further may be reshaped (e.g., collimated, focused, diverged, diffracted, etc.), without requiring use of an optical element such as a lens (e.g., a ball lens). For example, the structured reflective surface may have a surface profile that focuses or collimates light in addition to redirecting (e.g., turning) light.
In reference to the embodiment illustrated by
The curved structured reflective surface serves the functions of both a reflective surface (i.e., redirecting incident light) and an optical element (i.e., reshaping incident light). It may have a reflective surface profile conforming to an optical element such as ball lens, spherical lens, plano-convex lens, concave lens, or a combination thereof. As a result, the structured reflective surface of the present invention permits more options for reshaping light beam as compared to a ball lens.
In accordance with another embodiment of the present invention,
In a further embodiment (not illustrated), a ball lens may be provided (including a corresponding seat provided on the optical bench) to define the desired optical path in conjunction with a structured reflective surface.
In all the above described embodiments, the structured reflective surface may be configured to be flat, concave or convex, or a combination of such to structure a compound reflective surface. In one embodiment, the structured reflective surface has a smooth (polished) mirror surface. It may instead be a textured surface that is reflective. The structured reflective surface may have a uniform surface characteristic, or varying surface characteristics, such as varying degree of smoothness and/or textures across the surface, or a combination of various regions of smooth and textured surfaces making up the structured reflective surface. The structured reflective surface may have a surface profile and/or optical characteristic corresponding to at least one of the following equivalent optical element: mirror, focusing lens, diverging lens, diffraction grating, or a combination of the foregoing. The structure reflective surface may have a compound profile defining more than one region corresponding to a different equivalent optical element (e.g., a central region that is focusing surrounded by an annular region that is diverging).
In one embodiment, the structured reflective surface is defined on an opaque material that does not transmit light through the surface.
As can be appreciated from all of the foregoing, compared to silicon optical benches, the advantages of stamped optical benches include: stamping facilitates high throughput mass production of optical benches at with tight tolerances and lower costs; stamped surface features on the optical benches facilitate precise, passive optical alignment of optical elements and optical components mounted on the optical benches (e.g., light source/sensor, ball lens, optical fiber, etc.), stamping operations yield reflective optics that are already precisely aligned in relation to the stamped surface features; the stamped optics reduce the need for separate optical elements. The stamped optical benches may replace the silicon optical benches in the prior art optical subassemblies of a transmitter (Tx), a receiver (Rx), and/or a transceiver (Tx/Rx).
While the invention has been particularly shown and described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit, scope, and teaching of the invention. Accordingly, the disclosed invention is to be considered merely as illustrative and limited in scope only as specified in the appended claims.
This application is a continuation of U.S. patent application Ser. No. 14/695,008 filed on Apr. 23, 2015, which is a continuation-in-part of U.S. patent application Ser. No. 13/861,273 filed on Apr. 11, 2013, which (a) claims the priority of U.S. Provisional Patent Application No. 61/623,027 filed on Apr. 11, 2012; (b) claims the priority of U.S. Provisional Patent Application No. 61/699,125 filed on Sep. 10, 2012; (c) is a continuation-in-part of U.S. patent application Ser. No. 13/786,448 filed on Mar. 5, 2013, which claims the priority of U.S. Provisional Patent Application No. 61/606,885 filed on Mar. 5, 2012. These applications are fully incorporated by reference as if fully set forth herein. All publications noted below are fully incorporated by reference as if fully set forth herein.
| Number | Date | Country | |
|---|---|---|---|
| 61623027 | Apr 2012 | US | |
| 61699125 | Sep 2012 | US | |
| 61606885 | Mar 2012 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14695008 | Apr 2015 | US |
| Child | 16372361 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13861273 | Apr 2013 | US |
| Child | 14695008 | US | |
| Parent | 13786448 | Mar 2013 | US |
| Child | 13861273 | US |
