Ultra-Broadband Polarization Beam Splitter Based on Cascaded Mach-Zehnder Interferometers Assisted by Effectively Anisotropic Structures

An ultra-broadband polarization beam splitter (PBS) consisting of cascaded Mach-Zehnder interferometers (MZIs) is proposed on 220 nm-thick silicon-on-insulator (SOI) platform. The configuration the MZIs has a point symmetry in order to broaden bandwidth cross-coupling for TM polarization. sub-wavelength grating (SWG) structures act as effectively anisotropic cladding enhance separation two fundamental polarizations. Two filters with bends and Bragg reflection structure at outputs, respectively, are used further improve extinction ratio (ER). PBS remarkable performance ER > 20 dB over record broad 310 nm (IL <; 0.5 dB) or 350nm 1 both TE inputs.