On-chip integrated device for polarization-independent electro-optic modulation and wavelength division multiplexing

Abstract We propose an integrated device for polarization-independent electro-optic (EO) modulation and wavelength division multiplexing (WDM). The device is composed of a polarization splitter-rotator-combiner, a graphene EO modulator, and a photonic crystal wavelength division multiplexer. The TE 0 and TM 0 modes at wavelengths of 1550 nm and 1553.2 nm are combined after polarization rotation, then modulated by the modulator to achieve on-state and off-state. Finally, the two wavelengths of light are output as TE 0 modes from the same port of the wavelength division multiplexer. The simulation results based on the three-dimensional finite-difference time-domain method show that the insertion loss of the integrated device is lower than 0.72 dB, the extinction ratio is greater than 21 dB, and the crosstalk is less than −37.5 dB. The integrated device can achieve polarization-independent EO modulation and WDM functionality.