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 μs. This device could be used in reconfigurable mode-division-multiplexing systems.