A Nonlinear Activation Function for Optical Neural Networks Using a Mach-Zehnder Interferometer with a III-V-on-Si Amplifier
Yu Zhang, Hong Deng, Emadreza Soltanian, Jing Zhang, Günther Roelkens, Wim Bogaerts · 2023
With the benefit of high speed, wide bandwidth, and low latency, optical neural networks (ONN) form a promising neuromorphic computing platform for accelerating artificial intelligence tasks. ONNs contain two kinds of fundamental functional operations: multiply-accumulate (MAC) stages and nonlinear activation function units, as shown in Fig. 1(a). In the past years, different optical MAC units have been developed using wavelength-division multiplexing (WDM) schemes [1]–[2] or coherent multipath interferometers [3]. However, the optical nonlinear activation function units still remain a challenge for the integration of large-scale ONNs. Most nonlinear activation functions are implemented in optical-electrical (OE) conversion schemes [2]–[3], where processing speed is limited by the latency time of OE conversion. Therefore, an integrated all-optical nonlinear activation function is an attractive solution for optical neuromorphic computing.