The method is self-aligning, avoids fundamental splitting losses, and uses only local feedback loops on controllable beam splitters and phase shifters. It could be implemented with Mach-Zehnder interferometers in planar optics. The method extended to multiple simultaneous mode. Abstract: We experimentally demonstrate a mode-selective ROADM for two transverse-electric modes using a mode-selective phase shifter in the switch. We show 40 Gbps NRZ transmission and 1. As. We designed a Reconfigurable Optical Add/Drop Multiplexer (ROADM) based on a subcarrier add/drop node in an optical communication system that is suitable for all kinds of optical multiplexing signals. © 2024 The Author (s) View More.