Nonlinear All-Optical Diffractive Deep Neural Network with 10.6 μm Wavelength for Image Classification

Table 1

The training time of the N-D²NN model using three ReLU activation functions for the MNIST dataset and Fashion-MNIST dataset.

	Training time (h)
	MNIST	Fashion-MNIST
Leaky-ReLU	28.1	28.2
PReLU	28.1	28.2
RReLU	27.9	28.0