Neuromorphic photonic circuit modeling in Verilog-A

One of the significant challenges in neuromorphic photonic architectures is the lack of good tools to simulate large-scale photonic integrated circuits. It is crucial to perform simulations on a single platform to capture the circuit's behavior in the presence of both optical and electrical components. Here, we adopted a Verilog-A based approach to model neuromorphic photonic circuits by considering both the electrical and optical properties. Verilog-A models for the primary optical devices, such as lasers, couplers, waveguides, phase shifters, and photodetectors, are discussed, along with studying the composite devices such as microring resonators. Model parameters for different optical devices are extracted and tuned by analyzing the measured data. The simulated and experimental results are also compared for validation of Verilog-A models. Finally, a single photonic neuron circuit is simulated by implementing input, weight, and non-linear activation function by using lasers, microring resonators, and modulator, respectively. Electro-optical rapid co-simulation would significantly improve the efficiency of optimizing the devices and provide an accurate simulation of the circuit performance.