Beam steering type 1:4 optical switch with polymer thermo-optic phase shifters in a silica arrayed-waveguide

Abstract

A beam steering type 1:4 optical switch with phase shifters in a silica arrayed-waveguide is proposed. It consists of collimating waveguide mirrors, an arrayed-waveguide which has deep trenches with polymer materials, and input/output waveguides. It can switch the output port of the incident light at high extinction ratio. The incident light is guided to the front mirror, collimated, and input to the arrayed-waveguide. Each waveguide in the arrayed-waveguide has the same length. The number of narrow trenches filled with polymer linearly increases in order. The refractive index of the polymer is set to the effective index of the single mode silica waveguide at certain temperature. The propagation direction of the output light from the arrayed-waveguide can be controlled by changing the temperature of the device because of the large thermo-optic coefficient of the polymer. The second mirror converges the light into one of the output waveguide.We designed two types of the switch which had 9 or 15 waveguides in the arrayed waveguide and they are under fabrication. The chip sizes are about 2.5 mm x 8.0 mm and 2.5 mm x 9.0 mm, respectively. The required temperature shift for the switching from one output port to the adjacent output port is 20 [K] when we use the polymer with a TO coefficient of -1.8x10 -4 [1/K].