On-chip polarization splitter using total internal reflection mirrors on thick SOI platform

Wavelength independent manipulation of the state of polarization is essential for realizing broadband photonic integrated circuits (PICs). We present here, for the first time, the use of compact total internal reflection (TIR) mirrors in silicon waveguides to achieve wavelength-independent (within the limits of material dispersion), polarization-dependent phase shifts, which are also tolerant to fabrication errors. A potential application area is polarization splitters operating on a broad wavelength range that has been the focus of our first proof-of-concept demonstration. Our devices achieved a 15 dB polarization extinction ratio for 80 nm bandwidth for TE and TM polarized light. These broadband polarization splitters, when combined with polarization rotators, can be used to develop all-silicon fully integrated isolators and circulators.