On-chip hybrid demultiplexer for mode and coarse wavelength division multiplexing

Abstract

We propose a hybrid demultiplexer for mode and coarse wavelength division multiplexing on silicon-on-insulator (SOI) nanowires and photonic crystal (PhC) slab. First, a V-shape waveguide–cavity–waveguide filter based on PhC slab is presented. Coupling of resonant modes is introduced to the filter to suppress the crosstalk caused by connection with nanowires. Then, we cascade and optimize the filter to compose a coarse wavelength division demultiplexer. After that, a hybrid demultiplexer is constructed by combining the coarse wavelength division demultiplexer on PhC slab and mode division demultiplexer on SOI nanowires. The parameters of the hybrid demultiplexer are calculated using three-dimensional finite-difference time-domain (3D-FDTD) method. The numerical results show that the fundamental transverse electric ( $$\hbox {TE}_0$$ ) modes and the first-order TE ( $$\hbox {TE}_1$$ ) modes of 1530 nm and 1550 nm can be demultiplexed. The insertion loss is smaller than 2.0 dB, and the channel crosstalk is less than − 25 dB. The hybrid demultiplexer can be applied in a system that using mode and coarse wavelength division multiplexing simultaneously.