On-chip polarization-division multiplexing link assisted with triple-waveguide couplers

An on-chip silicon polarization-division multiplexing link assisted with triple-waveguide couplers is proposed and experimentally demonstrated on a silicon-on-insulator platform. It consists of a polarization beam splitter, a trunk waveguide, and a polarization beam combiner. The coupling strength can be reinforced with the help of the middle waveguide. The proposed device is optimized with a 7 µm coupling length, insertion losses of 0.12 and 0.64 dB, and polarization extinction ratios of 31.2 and 15 dB for the TM and TE polarizations, respectively, at 1550 nm. The fabrication tolerances of the device are also analyzed with the fabrication errors of ± 20 n m . Over a 100 nm bandwidth from 1500 nm to 1600 nm, the measured polarization extinction ratios are above 15.4 dB and 10.6 dB for TM and TE polarizations, respectively. The corresponding measured insertion losses are below 2 dB and 2.4 dB. The proposed polarization-division multiplexing link can be applied in optical communications and interconnects for signal routing.