Compact high-performance polarization beam splitter based on a silicon photonic crystal heterojunction

Abstract A novel polarization beam splitter based on a silicon photonic crystal (PC) heterostructure operating in the optical-telecommunications band is envisaged and is configured for planar integration with other PC or waveguide structures. The small 9 μm × 9.4 μm footprint polarization beam splitter is investigated by the plane-wave expansion and finite-difference time-domain methods. Due to the combined effects of self-collimation and the photonic band gap, self-collimation transmission and 90° beam splitting for the two orthogonal polarizations are achieved. The transmissivity exceeds 60% (78%) for TE (TM) polarization covering a 115-nm bandwidth, and it is also observed that the polarization extinction ratios of the device are higher than 13 and 31 dB, respectively. Moreover, at the wavelength of 1550 nm, TE (TM) polarization has high transmissivity 94.9% (88%) with high polarization extinction ratio of 17 dB (41 dB). A compact and efficient polarization beam splitter is successfully designed for applications in optical communications.