Integrated-optic polarization rotator with obliquely deposited columnar thin film

A new integrated-optic polarization rotator with anisotropic cladding formed by oblique angle deposition is presented. Optical anisotropy with tilt principal axes in the obliquely deposited columnar thin film induces hybrid polarization modes in the waveguide and thus produces polarization rotation. The dependence of device characteristics on columnar film parameters, such as column angle, film thickness, extraordinary index, and optical anisotropy, is investigated by 3D full-vectorial finite difference beam propagation method. The polarization rotator with Ta2O5 columnar thin film has polarization conversion efficiency as high as 99% and extinction ratio of 25dB.