Neuromorphic photonics with coherent linear neurons

An optical neural network (800) comprising:

• a plurality of optical neurons each comprising:
• a multipath interferometer comprising a plurality of parallel optical interferometer branches (210) coupled between an optical splitter (206) and an optical combiner (208), the optical interferometer branches (210) comprising a plurality of input branches (214) associated with neuron inputs and each comprising a first amplitude modulator (226), a second amplitude modulator (226), and at least one phase shifter (228), the optical combiner (208) configured to operatively generate an optical interference signal from modulated optical carrier signals output by the plurality of optical interferometer branches (210);
• electronic driver circuitry (224) configured to operatively control the first and second amplitude modulators (220) (218) and the phase shifters (318) (314) (222) in the input branches (214) to impart the signed neuron inputs and signed neuron weights onto optical carrier signals in the respective input branches (214) to generate the modulated optical carrier signals output by the input branches (214);
• and
• a non-linear activation and conversion unit (204), coupled to an output of the optical combiner (208) and comprising a photodetector (236), to generate an electronic neuron output (108) signal (230);
• and
• electronic control circuitry configured to determine, from the electronic neuron output (108) signal (230) of at least one of the plurality of optical neurons, a neuron input to another one of the plurality of optical neurons.

An optical neuromorphic computing method (900) employing an optical neuron (200) comprising a multipath optical interferometer, the method comprising:

• splitting light between multiple optical interferometer branches (210) of the multipath optical interferometer into multiple respective optical carrier signals, each of the multiple optical interferometer branches (210) having an associated neuron input and an associated neuron weight;
• modulating field amplitudes and phases of the optical carrier signals in the optical interferometer branches (210) to separately impart the associated neuron inputs and the associated neuron weights onto the optical carrier signals;
• and
• recombining the optical carrier signals at outputs of the optical interferometer branches (210) to generate an optical interference signal indicative of a weighted sum of the neuron inputs.