Mode-Selective Switch Based on Thermo-Optic Asymmetric Directional Coupler

Abstract

We propose a simple thermo-optic mode-selective switch based on an asymmetric directional coupler formed with a two-mode waveguide and a single-mode waveguide, where two electrodes heaters are deposited, respectively, on the two waveguides. Depending on which heater is turned on, either one of the two modes in the two-mode waveguide can be selectively switched to the single-mode waveguide or vice versa. Our typical experimental device fabricated with polymer material, which has a total length of 16.5 mm, shows extinction ratios higher than ~10 dB in the C-band for both modes. The switching powers for the two modes are 52 and 109 mW, respectively, and the corresponding switching times are 300 and 400 $\mu \text{s}$ . This device could be used in reconfigurable mode-division-multiplexing systems.