Table 1.

Summary of the key components of artificial neural networks

Components	Functions	Photonic devices
Axon and dendrite	Interconnection	Free space12, waveguides13–15
Soma	Summation and thresholding	Photodetectors12–15, electric-optic modulators14, light sources (LED and laser)12, optical amplifiers52, saturable absorbers52, optical bistable devices53
Synapse	Weighting	Hologram12, MZI15, micro-ring resonators14
	Memory	Electronic memories12–15, reversible optical memories54