Self-collimating polarization beam splitter based on photonic crystal Mach-Zehnder interferometer

Due to different boundary continuity conditions, electromagnetic waves with transverse-magnetic and transverse-electric polarizations respond differently when they encounter dielectric interfaces. Based on this mechanism, we propose a self-collimating polarization beam splitter (PBS) constructed on a polarization-insensitive self-collimation photonic crystal. The splitting is realized on a Mach-Zehnder interferometer (MZI), through which the two polarizations can be separated by 90 with low cross talk. Both polarizations are self-collimated to eliminate the diffraction loss during the propagation. Furthermore, the out-of-plane scattering loss is suppressed since the PBS is operated in the first band. The wavelength bandwidth of the MZI-based PBS reaches about 100 nm at 1550 nm. Finally, the influences of interfaces on the performance of the PBS are discussed. (C) 2010 Optical Society of America