New compact polarization rotator in anisotropic LiNbO3 graded-index waveguide.

The new compact polarization rotator in anisotropic graded index Ti:LiNbO(3) channel waveguide is proposed and investigated by 3D beam propagation method (BPM). Device is based on a channel optical waveguide directed at small angle (about 5 degrees) with respect to Z-axis on Y-cut lithium niobate substrate. The polarization conversion from quasi-TE to quasi-TM guided modes (and backwards) along 8 mm long waveguide with an index contrast 0.015, has been numerically demonstrated. Device is intended for polarization diversity of integrated optic elements based on LiNbO(3) structures.