Abstract: Processing elements for neural network accelerators, and methods of operating the processing elements. Each of a plurality of synapse lanes outputs an electrical signal indicative of a value of a synapse. Each electrical signal is received by a respective optical AND unit including an optical microring resonator that selectively couples an optical signal indicative of the value of an input neuron based at least in part on the received electrical signal. The output of each optical AND unit is provided to either an electrical multiply and accumulate unit, or a respective interferometer of a plurality of interferometers. The interferometers are arranged in series so that optical signals are sequentially summed and shifted by each interferometer. The last interferometer outputs a shifted and accumulated sum of the outputs received from the optical AND units. In either case, the accumulated sum may then be used to generate an output neuron.

Abstract: Devices and methods for performing computations for neural networks. A photonic locally-connected unit for a neural network accelerator includes a plurality of optical modulators, a positive accumulation waveguide, a negative accumulation waveguide, a plurality of optical adders, and first and second photodetectors. Each optical modulator receives a respective input optical signal and a respective electrical signal. Each optical signal is indicative of a value of input element, and each electrical signal is indicative of the value of a weight. Each optical modulator modulates the received input optical signal with the received electrical signal to generate a weighted optical signal. Each optical adder selectively couples one of the respective weighted optical signals into one of the positive or negative accumulation waveguides based on whether the respective weight is positive or negative.

Abstract: Processing elements for neural network accelerators, and methods of operating the processing elements. Each of a plurality of synapse lanes outputs an electrical signal indicative of a value of a synapse. Each electrical signal is received by a respective optical AND unit including an optical microring resonator that selectively couples an optical signal indicative of the value of an input neuron based at least in part on the received electrical signal. The output of each optical AND unit is provided to either an electrical multiply and accumulate unit, or a respective interferometer of a plurality of interferometers. The interferometers are arranged in series so that optical signals are sequentially summed and shifted by each interferometer. The last interferometer outputs a shifted and accumulated sum of the outputs received from the optical AND units. In either case, the accumulated sum may then be used to generate an output neuron.