Self-collimation Mach-Zehnder interferometer based polarization-independent beam splitter

A polarization-independent beam splitter (PIBS) based on self-collimation Mach-Zehnder interferometer (SMZI) in a hole-type silicon photonic crystal (PC) is proposed and numerically demonstrated. Utilizing polarization dependence of the transmission spectra of the SMZI and polarization transmission matching method, the SMZI can work as a PIBS by selecting appropriate path length difference in the structure. For a certain operating frequency, the PIBS has the same splitting ratio for both transverse-electric mode and transverse-magnetic mode. In this paper, the PIBS with splitting ratios of 1: 1 and 1: 2 is designed and numerically demonstrated, respectively. For the operating wavelength of 1550 nm, the sizes of the PIBS are only 19.7 mu m x 19.7 mu m. With its small dimensions, simple structure, and silicon- based material, this PIBS may have practical applications in photonic-integrated circuits. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE).