Recent Progress in Photonic Synapses for Neuromorphic Systems

TLDR

Photonic synapses, which use light to emulate synaptic functions, offer ultrahigh propagation speed, high bandwidth, low crosstalk, noncontact writing, and real‑time image processing, and have attracted extensive design and fabrication efforts. This review summarizes the development of photonic synaptic devices based on memristors, field‑effect transistors, and phase‑change memory, discusses their innovative applications in neuromorphic systems, and outlines current challenges and future research directions. The authors examine how emerging materials—memristors, field‑effect transistors, and phase‑change memory—are integrated into photonic synaptic architectures to achieve synaptic functionality.

Abstract

Implementing synaptic functions with electronic devices is critical to achieve neuromorphic systems on the hardware platform, as synapses play important roles in brain computing and memory. Synapses modulated by light signals, which are also referred as photonic synapses, can not only make effective use of the outstanding properties of light to provide devices with ultrahigh propagation speed, high bandwidth and low crosstalk but also provide a noncontact writing method, which can facilitate the evolution of optical wireless communication and operation. More importantly, real‐time image processing can also be performed by photonic synapses which possess temporary memory. Thus far, tremendous efforts have been taken to design and fabricate photonic synapses. Herein, a summary of the development of different kinds of emerging materials utilized in photonic synaptic devices including memristors, field‐effect transistors, and phase change memory is presented, followed by the innovative applications of photonic synapses for neuromorphic systems. Finally, some current challenges and future study directions are discussed.