Optical Shuffle Computation Network Using Multicore Fiber Arrays
20220413312 · 2022-12-29
Inventors
- Dane R. Austin (Pacifica, CA, US)
- William Andregg (Palo Alto, CA, US)
- Erik C. Nelson (Boise, ID, US)
- Robert T. Weverka (Boulder, CO, US)
Cpc classification
G02B3/0056
PHYSICS
G02B6/2713
PHYSICS
G02B3/0075
PHYSICS
H04B10/801
ELECTRICITY
G02B3/0068
PHYSICS
International classification
Abstract
Optical communication system communicates between an array of originating tiles and an array of terminating tiles. Each array is associated with a lenslet array, such as a two-layer array. Each originating tile has an array and each terminating tile has an array of transceivers. Each tile is associated with a common lenslet or lenslet pair. A beamlet from a representative originating transceiver passes through the lenslet pair adjacent to its tile via an originating Fourier transform element, collimating optics, and a terminating Fourier transform element. The beam then passes through the lenslet pair adjacent to the tile containing the terminating transceiver associated with the representative originating transceiver, and is focused onto that receiver by that lenslet pair. Originating and/or terminating arrays of multicore fibers may be used between the originating transceivers and the originating Fourier transform element and/or between the terminating Fourier transform element and the terminating transceivers.
Claims
1. Apparatus for optical communication comprising: an originating chip segment comprising an originating tile, the originating tile comprising arrays of originating transceivers configured to transmit beamlets outward from the tile; a terminating chip segment comprising a terminating tile, the terminating tile comprising arrays of terminating transceivers; wherein each terminating transceiver corresponds to a single originating transceiver; an originating array of multicore fibers having originating-chip-proximate ends adjacent to the originating transceivers and configured to receive beamlets from the originating transceivers and deliver them via cores to originating-chip-distal ends of the originating array of multicore fibers to form exiting beams; an originating Fourier transform element disposed at the distal ends of the originating array of multicore fibers and configured such that the location of a core determines the direction of its exiting beam after the originating Fourier transform element; optics for collimating the exiting beams; a terminating Fourier transform element for receiving the exiting beams and configured such that the direction of each collimated beam determines the location of the beam after the terminating Fourier transform element; a terminating array of multicore fibers having terminating-chip-proximate ends adjacent to the terminating chip segment such that beams exiting cores of the terminating array of multicore fibers enter terminating transceivers; wherein terminating-chip-distal ends of the terminating array of multicore fibers are adjacent to the terminating Fourier transform element and receive beams from the terminating Fourier transform element and transmit them to the terminating transceivers.
2. The apparatus of claim 1 configured to also operate in the reverse direction, wherein a beam from a terminating transceiver is directed to its corresponding originating transceiver.
3. The apparatus of claim 1 wherein the originating chip segment comprises collected tiles, and the terminating chip segment comprises dispersed tiles (designated itels).
4. The apparatus of claim 1 wherein the originating Fourier transform element comprises an originating lenslet array comprising a first originating layer and a second originating layer of lenslets parallel and adjacent to each other and to the array of originating tiles, the lenslets in the first originating layer forming originating lenslet pairs with the lenslets in the second originating layer, the originating lenslet pairs constructed and arranged to collimate beams from transmitters such that the location of a transmitter within its tile determines the direction of its resulting collimated beam.
5. The apparatus of claim 1 wherein the terminating Fourier transform element comprises a terminating lenslet array comprising a first terminating layer and a second terminating layer of lenslets parallel and adjacent to each other and to the array of terminating tiles, the lenslets in the first terminating layer forming terminating lenslet pairs with the lenslets in the second terminating layer, the terminating lenslet pairs constructed and arranged to focus collimated beams to receivers such that the direction of a collimated beam determines the receiver it is focused on.
6. Apparatus for optical communication comprising: an originating chip segment comprising an originating tile (92300), the originating tile comprising arrays of originating transceivers configured to transmit beamlets outward from the tile; a terminating chip segment comprising a terminating tile, the terminating tile comprising arrays of terminating transceivers; wherein each terminating transceiver corresponds to a single originating transceiver; an originating Fourier transform element configured such that the location of a beamlet determines the direction of its exiting beam after the originating Fourier transform element; optics for collimating the exiting beams; a terminating Fourier transform element for receiving the exiting beams and configured such that the direction of each collimated beam determines the location of the beam; wherein the originating chip segment comprises collected tiles, and the terminating chip segment comprises dispersed tiles (designated itels).
7. The apparatus of claim 6 configured to also operate in the reverse direction, wherein a beam from a terminating transceiver is directed to its corresponding originating transceiver.
8. The apparatus of claim 6, further comprising an originating array of multicore fibers having originating-chip-proximate ends adjacent to the originating transceivers and configured to receive beamlets from the originating transceivers and deliver them via cores to the originating Fourier transform element.
9. The apparatus of claim 8, further comprising a terminating array of multicore fibers having terminating-chip-proximate ends adjacent to the terminating chip segment such that beams exiting cores of the terminating array of multicore fibers enter terminating transceivers; wherein terminating-chip-distal ends of the terminating array of multicore fibers are adjacent to the terminating Fourier transform element and receive beams from the terminating Fourier transform element and transmit them to the terminating transceivers.
10. Apparatus for optical communication comprising: means for providing beamlets from originating transceivers on originating tiles; originating Fourier transform means for converting the location of the beamlets to directions of the beamlets to generate directed beams; means for collimating the directed beams; terminating Fourier transform means for converting the location of the collimated beams to a location of the collimated beams, to generate located beams; means for providing beamlets to terminating transceivers wherein each originating transceiver corresponds to a single terminating transceiver such that a beamlet from an originating transceiver arrives as a located beam at its corresponding terminating transceiver; and wherein the originating tiles are collected tiles having their transceivers closely spaced physically and the receiving tiles are dispersed itels having their transceivers scattered physically.
11. The apparatus of claim 10 further comprising multicore fibers between the originating transceivers and the originating Fourier transform means for transmitting the beamlets to the originating Fourier transform means.
12. The apparatus of claim 10 further comprising multicore fibers between the terminating Fourier transform means and the terminating transceivers for transmitting the located beams to the terminating transceivers.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DESCRIPTION OF SPECIFIC EMBODIMENTS
[0044] The following description sets forth embodiments of an optical shuffle computation network according to the invention. Embodiments of the invention can be applied to computational environments such as artificial neural network systems, array computation, memory access and to networked computational systems.
[0045] The general functionality of the optical shuffle computation network is to accept signals from an array of collected tiles, transmit signals from each over a long range to a set of dispersed tiles, where the signals may access memory and where the signals may be exchanged locally and transmitted back to the original or to an exchanged collected tile.
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[0047] Originating transducer array has four tiles 410, 420, 430, and 440 with nine pixels or transducers (receivers, transmitters, modulators, etc.) each (in the one dimension shown). The second pixel in the first tile 410 is pixel 412. In general, pixels are designated something like P.sub.tile,pixel so pixel 412 is OP.sub.1,2 in that notation. To avoid confusion in this description, a different reference number is used for each pixel discussed. Pixel 437 is seventh pixel in the third tile, 430. It could be designated OP.sub.3,7.
[0048] Terminating transducer array 600 has nine tiles 610, 620, 630, 640, 650, 660, 670, 680, and 690 with 4 pixels each. Pixel 621 (TP.sub.2,1) is the first pixel in the second tile and pixel 673 (TP.sub.7,3) is the third pixel in the seventh tile 670.
[0049] This embodiment may be bidirectional. In this discussion, transmission originates from collected array 400, so transducers 401-440 on the collected side are sometimes designated transmitter-receivers. The signals originating from array 400 terminate at dispersed array 600, and so transducers 601-690 on the dispersed side are sometimes designated receiver-transmitters.
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[0051] Quarter-wave plates 40 and 60 rotate polarization of light from light sources 800, 100, so that after reflective modulation the light passes straight through polarizing beam splitters 31 and 30 from array 400 to array 600 and (in a two-way system) from array 600 to array 400. Optoelectronic transducers on array 400 and array 600 may operate as reflective modulators in signal transmitting mode, or as detectors in signal receiving mode.
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[0053] Two-layer lenslets in arrays 500 and 700 operate as Fourier transform pairs for the tiles in arrays 400 and 600. Each tile faces a pair of lenslets (e.g. tile 410 faces lenslets 510 and 511). The cone of light from the transducer 412 is turned by the first lenslet 510 and the second lenslet collimates the light, directed at an angle corresponding to the position of the transducer. The lenslets 510 and 511 have a common focal length and are separated by a distance equal to the focal length. The lens pair 44 and 64 also have a common focal length and are separated by a distance equal to the focal length, making an additional Fourier transform pair. The transmitters may be densely packed, meaning that the distance between adjacent transmitters on a tile is on the order of an f-number of the originating lenslet array pair times a wavelength of light being transmitted by the transmitters. This allows the receiving lenslets 700 to also be densely packed, since the combination of lenslets 510, 511 and lenses 44,64 form a magnifying imaging system from the transducers in the tile 410 to the light entering the lenslet array 700. The two lens Fourier transform pairs create a compact optical system where light cones from one tile do not overlap the light cones from the adjacent tiles prior to exiting the lenslet array, when the tiles are densely packed, meaning that the distance between adjacent tiles is much smaller than the width of the tile—on the order of the distance between transmitters rather than the width of a tile.
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[0056] As a specific example, lenslet 522 converts transmitted beamlet 150 into directed beamlet 152. Lenslet 524, along with lens 44 converts directed beamlet 152 into collimated beamlet 158. At the receiving end, lenslet 524 along with lens 64 converts collimated beamlet 158 into focused beamlet 164 which is received by receiver 621.
[0057] Thus transmitter 412 corresponds to receiver 621 (and vice versa in the case of a reverse operating system where transmitter 412 is a transmitter-receiver and receiver 621 is a receiver-transmitter).
[0058] With optoelectronic transducer 412 acting as a reflective modulator, the circularly polarized light 150 coming from 412 is directed 152 by lenslet 522 towards the center of lenslet 524. Lenslet 524 collimates directed beamlet 152 into collimated beamlet 158, at an angle substantially proportional to the position of the optoelectronic transducer 412 within tile 410. Lens 44 bends beamlet 158 toward the center of the optical train. Quarter-wave plate 40 converts the circularly polarized light in the beamlet to p-polarized light that is transmitted by polarizing beam splitters 31 and 30. Quarter-wave plate 60 converts the light in the beamlet to circular polarization and lens 64 bends this beamlet toward the center of the optical train. A lenslet pair in lenslet array 700 focuses the light onto optoelectronic transducer 621 in tile 620. Optoelectronic transducer 621 acting as an optical detector converts the signal from optical to electronic.
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[0061] Returning to
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[0066] Compact subarrays are enabled by the two lenslet Fourier transform. Two lenses separated by their focal length perform a Fourier transform of the light field. The lenslet nearest the modulator plane, 1530, steers the rays from each modulator/detector towards the center of a second lens, 1531. The second lens collimates these rays. This compact system allows one to densely pack subarrays at the input and output of a transposer, with minimal gaps between subarrays.
[0067] An optical transposer may be used in a neural network. We put a systolic-array matrix-multiplier on each subarray on one side of the transposer, and we put routing and memory on the other side of the transposer. This creates a connected set of systolic-array matrix-multipliers whose connections can be reconfigured on the routing and memory side. Memory registers are all a short distance from each systolic array due to the long range distributed connectivity of the transposer. This enables an efficient artificial neural network, since signal routing and memory access are the high latency, high energy dissipation parts of neural networks in current technology.
[0068] A system that moves blocks of data large distances by communicating blocks of data (tiles) with the use of a transpose, performing the same short-distance shift on each component of the dispersed block of data (itels), transposing back again so that the block of data (tile) is reconstructed with a large-distance shift proportional to the short-distance shift performed on each component.
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[0079] Note that the numbering of elements is slightly different than in previous figures, because
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[0083] Fourier transform elements 700 convert the position of the signals from fiber 62,300 to angles as shown in, for example,
[0084] Next the signals are transmitted to the terminating side of the device. Fourier transform elements 500 convert the angles of the arriving signals to positions to match them up with cores in terminating side multicore fiber 41,400. In
[0085] Returning to
[0086] The preceding describes just one optical pathway within one embodiment of the invention. Other pathways in the same embodiment connect additional pairs of originating transceivers to terminating transceivers. One pathway (in dotted lines) may couple light from originating transceiver 92350 to its terminating transceiver (not shown) on terminating tile 100050. Said light may couple through the same originating multicore fiber 62300, the same originating Fourier transform element 700, and the same array scale Fourier transform optics 65. For the transceiver 92350, the light will pass through a different terminating Fourier transform element 500B, and a different terminating multicore fiber 40050 such that it lands on a terminating transceiver placed on a different terminating tile 100050.
[0087] Another distinct pathway of the preceding embodiment may couple light emitted by a terminating transceiver 101123 back through the system such that the light illuminates an originating transceiver 92311.
[0088] Another distinct pathway of the preceding embodiment may start with light emitted from an originating transceiver on a different originating tile (not shown) such that the light passes through a different originating multicore fiber (not shown) in the originating array of multicore fibers (not shown). Said light will propagate through the array scale Fourier transform optics 65 such that it is transmitted through its terminating Fourier transform element 500 and then couples into a core within the terminating multicore fiber (40023) within the terminating array of multicore fibers, landing on a different terminating transceiver than the one labeled 101123 within the terminating tile 100023.
[0089] Another distinct pathway of the preceding embodiment may start with light emitted from an originating transceiver on a different originating tile (not shown) such that the light passes through a different originating multicore fiber (not labeled) in the originating array of multicore fibers (not labeled). Said light will propagate through the array scale Fourier transform optics 65 such that it is transmitted through a different terminating Fourier transform element (not labeled) within the terminating array of Fourier transform elements and then couples into a core within a different terminating multicore fiber (not labeled) within the terminating array of multicore fibers, landing on a different terminating transceiver within a different terminating tile.
[0090] In another embodiment, one or more originating tiles may be placed on one or more originating chip segments (not shown) which are distinct from the originating chip segment 90000 shown. In an extension of said embodiment, originating transceivers in originating tiles placed on the distinct originating chip segment may emit light which illuminates one terminating transceiver on the terminating tile 100023 shown here. In a separate extension of said embodiment, originating transceivers in originating tiles placed on the distinct originating chip segment may emit light which illuminates one terminating transceiver on a different terminating tile.
[0091] In another embodiment, one or more terminating tiles may be placed on one or more terminating chip segments which are distinct from the terminating chip segment 100000. In an extension of said embodiment, light emitted by one originating transceiver on the originating tile 92300 may illuminate terminating transceivers on the terminating tile placed on the distinct terminating chip segment. In another extension of said embodiment, light emitted by a different originating transceiver on a different originating tile 92300 may illuminate terminating transceivers on the terminating tile placed on the distinct terminating chip segment.
[0092] In one embodiment, light emitted by an originating transceiver may be emitted directly into one core of the multicore optical fiber in contact with the transceiver. In an alternative embodiment, the multicore optical fiber is not in contact, but is placed sufficiently close to couple light from the transceiver into one core of the multicore optical fiber. In an alternative embodiment, light emitted by an originating transceiver may be coupled into one core of the multicore optical fiber through a waveguide.
[0093] In one embodiment, light emitted by an originating transceiver may be coupled into one core of a multicore fiber using a lens. In one variation of said embodiment, the lens may be a bi-telecentric lens such as described by USPTO application 63/286,450 which is incorporated herein by reference. In one embodiment, light is coupled between one core of a terminating multicore fiber and the terminating transceiver using a bi-telecentric lens.
[0094] Throughout the preceding embodiments of the invention, a single optical pathway connects a single originating transceiver to a single terminating transceiver. Throughout the preceding embodiments, a single instance of array scale Fourier transform optics was used. Throughout the preceding embodiments, a single originating array of multicore fibers was used. Throughout the preceding embodiments, a single terminating array of multicore fibers was used. Throughout the preceding embodiments, a single originating array of Fourier transform elements was used. Throughout the preceding embodiments, a single terminating array of Fourier transform elements was used.
[0095] The variations of the preceding embodiments may be further combined with the following. In alternative embodiments of the invention, multicore fibers may be separated among many originating arrays of multicore fibers. In alternative embodiments of the invention, multicore fibers may be separated among many terminating arrays of multicore fibers. In alternative embodiments, multiple originating Fourier transform elements may be separated into multiple originating arrays of Fourier transform elements. In alternative embodiments, multiple terminating Fourier transform elements may be separated into multiple terminating arrays of Fourier transform elements.
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[0098] The interconnection pattern is separable in each transverse dimension and the one-dimensional pattern is the same shuffle-exchange as shown
[0099] While the exemplary preferred embodiments of the present invention are described herein with particularity, those skilled in the art will appreciate various changes, additions, and applications other than those specifically mentioned, which are within the spirit of this invention. “Signals” can mean digital bits, digital on off, or phase and amplitude modulated signals, or analog. The optoelectronic transducer can be 2-mode semiconductor device, or polarization walk-off. The lenses 14,84,94,44,64, as shown all have same focal length, but can vary to expand beams or the like. Time multiplexing can be used for either transmit or receive or both. Optics for compact FT, tiles packing, transposer packing can be used.
[0100] The number of transmitters in an originating tile may be equal to the number of tiles in the destination or terminating array. The interconnection pattern between transmitters and receivers may be configured to be an N-way perfect shuffle. The transmitters may comprise LEDs or VCSELs.