Polarization beam splitter for two-dimensional photonic crystal self-collimation devices

摘要

In this paper, we propose a polarization beam splitter (PBS) for two-dimensional photonic crystal (2D PhC) self-collimation devices. By engineering the PhC dispersion characteristics, both transverse magnetic ? and transverse electric (TE) light can propagate collinearly in the same PhC by self-collimation phenomena. Either one or two defect regions are designed to pass the TM light and to reflect the TE light such that the two polarizations can be efficiently separated into different output ports. The finite-difference time-domain (FDTD) method is employed to assess the device performance. Polarization extinction ratios (PERs) between the two output ports are 25.4 dB and 31.8 dB for TM and TE inputs, respectively. This PBS also exhibits a large operating wavelength range (PER > 20 dB) covering all over the optical C-band and L-band. Fabrication tolerance for the radius of air holes is approximately 10 nm. Moreover, the size of the PBS is only 24 μm × 18 μm and can be even more compact for a lower PER.