Implementing a neuromorphic computing system using nanophotonic neurons

A neuromorphic computing system, comprising:

• a sequence of neural layers, wherein each neural layer comprises a set of photonic neurons, wherein each photonic neuron converts one or more optical input signals into corresponding electrical input signals, processes the electrical input signal to produce an electrical output signal, and converts the electrical output signal into an optical output signal;
• and
• a set of intervening optical interconnection networks, which couple together successive neural layers in the sequence of neural layers, wherein each interconnection network provides weighted links between photonic neurons in successive neural layers;
• wherein each photonic neuron comprises:
• a first photodiode coupled between an internal node and a drain voltage vd;
• a second photodiode coupled between ground and the internal node;
• an integrating capacitor coupled between the internal node and ground;
• a first transistor having a gate coupled to the internal node;
• a light-emitting output device coupled between a drain of the first transistor and the drain voltage vd;
• a second transistor having a gate coupled to a source of the first transistor and having a source coupled to ground;
• a first resistor coupled between the internal node and a drain of the first transistor;
• and
• a second resistor coupled between the gate of the second transistor and ground.

A three-dimensional (3D) integrated neuromorphic computing system, comprising:

• a stack containing computational planes, wherein each computational plane in the stack includes a nanophotonic neural network;
• wherein the stack additionally includes at least one memory plane containing nanophotonic memory elements;
• and
• wherein successive planes in the stack are coupled together through a set of vertical optical vias, each of which comprises:
• a bottom waveguide configured to convey light in a horizontal direction;
• an inverted 45-degree reflector configured to reflect horizontally propagating light from the bottom waveguide in a vertical direction;
• a vertical silicon escalator configured to convey light in a vertical direction from the inverted 45-degree reflector;
• a 45-degree reflector configured to reflect vertically propagating light from the vertical silicon escalator in a horizontal direction;
• and
• a top waveguide configured to convey light received from the 45-degree reflector in a horizontal direction.