Cascadable excitability and inhibition in DFB laser-based photonic spiking neurons

Effective communication between neurons is crucial in both the human brain and neuromorphic computing. Excitatory and inhibitory spiking information are transmitted through axons and dendrites to adjacent neurons. In this paper, we propose a cascaded system for excitability and inhibition in photonic spiking neurons based on distributed feedback (DFB) laser subject to side-mode optical pulse injection (SMOPI). The feasibility of the cascaded system is proved by simulation and experiment. This system offers the advantage of eliminating the need for additional amplifiers. By appropriately adjusting the injection optical power and wavelength detuning between two DFB lasers, neuronal excitability and inhibition can be cascaded successfully. Both temporal encoded spikes and rate encoded spikes are considered. The operating conditions of the two lasers employed in the cascaded system are also analyzed. This work provides a promising technical pathway for the development of photonic spiking neural network (PSNN) chips, leveraging the benefits of low power consumption and high integration.