Thermo-optic waveguide digital optical switch using symmetrically coupled gratings

A 2x2 digital optical switch using two symmetrical unidirectional Bragg grating couplers is proposed and studied in this paper. A low-loss polymer is used as waveguide material, and the Bragg grating coupling efficiency is optimized to be 22%, then the unidirectional coupling efficiency of 99.9% is achieved in theory. The performance of the switch based on the unidirectional couplers with Bragg gratings is theoretically modeled and simulated. Finally, the 2.4dB insertion loss, the -17dB crosstalk between two output ports, the 28 dB extinction ratio, the 1.5ms response speed and the 87mW power consumption are experimentally demonstrated with this regime.