Automated Optimization Algorithm for 16-channel Silicon WDM System Using 4-Level Cascaded Mach-Zehnder Interferometers

On-chip Wavelength Division Multiplexing (WDM) devices have been widely used in optical communications and signal processing to increase data throughput. As the number of wavelength channels increases, the performance of WDM devices is susceptible to various types of errors from fabrication, design and environmental changes. To address this issue, we demonstrate an automated optimization control method based on the Gradient-Descent algorithm and examine the performance of applying this algorithm to a silicon photonic 16-channel WDM device utilizing 4-level cascaded tunable Mach-Zehnder interferometers. The extinction ratio and crosstalk of all 16 channels are successfully optimized with different initial temperatures in simulation. This procedure provides a general approach to automated control and optimize complex photonic systems.