Efficient and broadband polarization rotator using horizontal slot waveguide for silicon photonics

We report an efficient and low-loss polarization rotator based on mode evolution using horizontal slot waveguide. The device is fabricated using complementary metal-oxide-semiconductor compatible processes, which allows monolithic integration with active drive electronics and other photonic components. A rotator fabricated with 100 mu m transition length provides a high extinction ratio >14 dB for both transverse-magnetic (TM)-transverse-electric (TE) and TE-TM rotation. The excess loss of the device is <1 dB for both rotations as etching of the bottom Si waveguide is prevented. The device also exhibits a uniform rotation response over C+L band wavelength range of 1530-1600 nm. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4734640]