Abstract:A reconfigurable optical add/drop multiplexer (ROADM) based on 2D photonic crystal is designed by using the structure of point and line defects and filling nonlinear material in point defects. According to the coupled mode theory, the external excitation light can make the incident wave not be coupled at the point defects, so as to achieve the wavelength reconfiguration. The numerical simulation results show that when the channel spacing is 20nm, the device can achieve high upload/download efficiency, high extinction ratio, fast response time and small size.