Abstract: Systems and methods for performing matrix operations using a path-number balanced optical network are provided. The optical network is formed as an array including active optical components and passive optical components arranged at a substantially central location of the array. The optical network includes at least NM active optical components which are used to implement a first matrix of any size N×M by embedding the first matrix in a second matrix of a larger size. The optical network performs matrix-vector and matrix-matrix operations by propagating one or more pluralities of optical signals corresponding to an input vector through the optical network.

Abstract: A training system for training a machine learning model such as a neural network may have a different configuration and/or hardware components than a target device that employs the trained neural network. For example, the training system may use a higher precision format to represent neural network parameters than the target device. In another example, the target device may use analog and digital processing hardware to compute an output of the neural network whereas the training system may have used only digital processing hardware to train the neural network. The difference in configuration and/or hardware components of the target device may introduce quantization error into parameters of the neural network, and thus affect performance of the neural network on the target device. Described herein is a training system that trains a neural network for use on a target device that reduces loss in performance resulting from quantization error.

Abstract: Systems and methods for increasing throughput of a photonic processor by using photonic degrees of freedom (DOF) are provided. The photonic processor includes a multiplexer configured to multiplex, using at least one photonic DOF, multiple encoded optical signals into a multiplexed optical signal. The photonic processor also includes a detector coupled to an output of an optical path including the multiplexer, the detector being configured to generate a first current based on the multiplexed optical signal or a demultiplexed portion of the multiplexed optical signal. The photonic processor further includes a modulator coupled to and output of the detector, the modulator being configured to generate a second current by modulating the first current.

Abstract: Aspects relate to a photonic processing system, a photonic processor, and a method of performing matrix-vector multiplication. An optical encoder may encode an input vector into a first plurality of optical signals. A photonic processor may receive the first plurality of optical signals; perform a plurality of operations on the first plurality of optical signals, the plurality of operations implementing a matrix multiplication of the input vector by a matrix; and output a second plurality of optical signals representing an output vector. An optical receiver may detect the second plurality of optical signals and output an electrical digital representation of the output vector.

Abstract: Hybrid analog-digital processing systems are described. An example of a hybrid analog-digital processing system includes photonic accelerator configured to perform matrix-vector multiplication using light. The photonic accelerator exhibits a frequency response having a first bandwidth (e.g., less than 3 GHz). The hybrid analog-digital processing system further includes a plurality of analog-to-digital converters (ADCs) coupled to the photonic accelerator, and a plurality of digital equalizers coupled to the plurality of ADCs, wherein the digital equalizers are configured to set a frequency response of the hybrid analog-digital processing system to a second bandwidth greater than the first bandwidth.

Abstract: Systems and methods for performing matrix operations using a path-number balanced optical network are provided. The optical network is formed as an array including active optical components and passive optical components arranged at a substantially central location of the array. The optical network includes at least NM active optical components which are used to implement a first matrix of any size N×M by embedding the first matrix in a second matrix of a larger size. The optical network performs matrix-vector and matrix-matrix operations by propagating one or more pluralities of optical signals corresponding to an input vector through the optical network.

Abstract: Low-noise optical differential receivers are described. Such differential receivers may include a differential amplifier having first and second inputs and first and second outputs, and four photodetectors. A first and a second of such photodetectors are coupled to the first input of the differential amplifier, and a third and a fourth of such photodetectors are coupled to the second input of the differential amplifier. The anode of the first photodetector and the cathode of the second photodetector are coupled to the first input of the differential amplifier. The cathode of the third photodetector and the anode of the fourth photodetector are coupled to the second input of the differential amplifier. The optical receiver may involve two stages of signal subtraction, which may significantly increase noise immunity.

Abstract: Photonic processors are described. The photonic processors described herein are configured to perform matrix-matrix (e.g., matrix-vector) multiplication. Some embodiments relate to photonic processors arranged according to a dual-rail architecture, in which numeric values are encoded in the difference between a pair optical signals (e.g., in the difference between the powers of the optical signals). Relative to other architectures, these photonic processors exhibit increased immunity to noise. Some embodiments relate to photonic processors including modulatable detector-based multipliers. Modulatable detectors are detectors designed so that the photocurrent can be modulated according to an electrical control signal. Photonic processors designed using modulatable detector-based multipliers are significantly more compact than other types of photonic processors.

Abstract: Photonic processors are described. The photonic processors described herein are configured to perform matrix-matrix (e.g., matrix-vector) multiplication. Some embodiments relate to photonic processors arranged according to a dual-rail architecture, in which numeric values are encoded in the difference between a pair optical signals (e.g., in the difference between the powers of the optical signals). Relative to other architectures, these photonic processors exhibit increased immunity to noise. Some embodiments relate to photonic processors including modulatable detector-based multipliers. Modulatable detectors are detectors designed so that the photocurrent can be modulated according to an electrical control signal. Photonic processors designed using modulatable detector-based multipliers are significantly more compact than other types of photonic processors.

Abstract: Photonic processors are described. The photonic processors described herein are configured to perform matrix multiplications (e.g., matrix vector multiplications). Matrix multiplications are broken down in scalar multiplications and scalar additions. Some embodiments relate to devices for performing scalar additions in the optical domain. One optical adder, for example, includes an interferometer having a plurality of phase shifters and a coherent detector. Leveraging the high-speed characteristics of these optical adders, some processors are sufficiently fast to support clocks in the tens of gigahertz of frequency, which represent a significant improvement over conventional electronic processors.

Abstract: Photonic processors are described. The photonic processors described herein are configured to perform matrix multiplications (e.g., matrix vector multiplications). Matrix multiplications are broken down in scalar multiplications and scalar additions. Some embodiments relate to devices for performing scalar additions in the optical domain. One optical adder, for example, includes an interferometer having a plurality of phase shifters and a coherent detector. Leveraging the high-speed characteristics of these optical adders, some processors are sufficiently fast to support clocks in the tens of gigahertz of frequency, which represent a significant improvement over conventional electronic processors.

Abstract: Optical chips and packages are described. The optical chips and packages described herein are configured to output high-power, single mode optical outputs for use by integrated photonics packages. Some embodiments relate to an optical chip or package including a light source array configured to output a plurality of first optical signals and an optical combiner configured to receive the plurality of first optical signals from the light source array and to output a second optical signal that is a combination of the received plurality of first optical signals. The optical combiner may include at least one tunable element configured to increase an optical power of the output second optical signal.

Abstract: Techniques for computing matrix operations for arbitrarily large matrices on a finite-sized hybrid analog-digital matrix processor are described. Techniques for gain adjustment in a finite-sized hybrid analog-digital matrix processor are described which enable the system to obtain higher energy efficiencies, greater physical density and improved numerical accuracy. In some embodiments, these techniques enable maximization of the predictive accuracy of a GEMM-based convolutional neural network using low-precision data representations.

Abstract: Described herein are photonic communication platforms that can overcome the memory bottleneck problem, thereby enabling scaling of memory capacity and bandwidth well beyond what is possible with conventional computing systems. Some embodiments provide photonic communication platforms that involve use of photonic modules. Each photonic module includes programmable photonic circuits for placing the module in optical communication with other modules based on the needs of a particular application. The architecture developed by the inventors relies on the use of common photomask sets (or at least one common photomask) to fabricate multiple photonic modules in a single wafer. Photonic modules in multiple wafers can be linked together into a communication platform using optical or electronic means.

Abstract: Photonic processors are described. The photonic processors described herein are configured to perform matrix-matrix (e.g., matrix-vector) multiplication. Some embodiments relate to photonic processors arranged according to a dual-rail architecture, in which numeric values are encoded in the difference between a pair optical signals (e.g., in the difference between the powers of the optical signals). Relative to other architectures, these photonic processors exhibit increased immunity to noise. Some embodiments relate to photonic processors including modulatable detector-based multipliers. Modulatable detectors are detectors designed so that the photocurrent can be modulated according to an electrical control signal. Photonic processors designed using modulatable detector-based multipliers are significantly more compact than other types of photonic processors.

Abstract: Described herein are photonic communication platforms and related packages. In one example, a photonic package includes a substrate carrier having a recess formed through the top surface of the substrate carrier. The substrate carrier may be made of a ceramic laminate. A photonic substrate including a plurality of photonic modules is disposed in the recess. The photonic modules may be patterned using a common photomask, and as a result, may share a same layer pattern. A plurality of electronic dies may be positioned on top of respective photonic modules. The photonic modules enable communication among the dies in the optical domain. Power delivery substrates may be used to convey electric power from the substrate carrier to the electronic dies and to the photonic substrate. Power delivery substrates may be implemented, for example, using bridge dies or interposers (e.g., silicon or organic interposers).

Abstract: Aspects relate to a photonic processing system, an integrated circuit, and a method of operating an integrated circuit to control components to modulate optical signals. A photonic processing system, comprising: a photonic integrated circuit comprising: a first electrically-controllable photonic component electrically coupling an input pin to a first output pin; and a second electrically-controllable photonic component electrically coupling the input pin to a second output pin.

Abstract: Described herein are photonic communication platforms that can overcome the memory bottleneck problem, thereby enabling scaling of memory capacity and bandwidth well beyond what is possible with conventional computing systems. Some embodiments provide photonic communication platforms that involve use of photonic modules. Each photonic module includes programmable photonic circuits for placing the module in optical communication with other modules based on the needs of a particular application. The architecture developed by the inventors relies on the use of common photomask sets (or at least one common photomask) to fabricate multiple photonic modules in a single wafer. Photonic modules in multiple wafers can be linked together into a communication platform using optical or electronic means.

Abstract: Techniques for computing matrix operations for arbitrarily large matrices on a finite-sized hybrid analog-digital matrix processor are described. Techniques for gain adjustment in a finite-sized hybrid analog-digital matrix processor are described which enable the system to obtain higher energy efficiencies, greater physical density and improved numerical accuracy. In some embodiments, these techniques enable maximization of the predictive accuracy of a GEMM-based convolutional neural network using low-precision data representations.

Abstract: The techniques described herein relate to methods and apparatus for interferometric modulation. An apparatus includes an interferometric device comprising a first optical path and a second optical path, and at least one Franz-Keldysh (FK) modulator disposed in either the first optical path or the second optical path of the interferometric device. The interferometric device receives input light, wherein a first portion of the input light travels along the first optical path of the interferometric device, and a second portion of the input light travels along the second optical path of the interferometric device. The FK modulator modulates an intensity of either the first portion of the input light or the second portion of the input light.