Towards integrated optical spiking neural networks: Delaying spikes on chip

To emulate Spiking Neural Networks (SNN) on an integrated photonic chip, one needs both excitable optical components, to mimic the spiking neurons, and delay lines acting as the connections that transfer the pulses between those neurons. Such an optical connection needs to have a delay in the order of magnitude of the internal timescale of the neuron. Recently, we showed how passive silicon-on-insulator microring resonators can be used as an all-optical spiking neuron. In this paper, we investigate how the dynamics of the microring can be used to obtain a meaningful spike delay. The possibility to delay spikes on chip paves the way towards fully integrated optical SNNs.