Beam propagation modeling of polarization rotation in deeply etched semiconductor bent waveguides

A rigorous study of polarization rotation in deeply etched semiconductor optical waveguide bends has been carried out and results are presented, using the finite element-based fully vectorial beam propagation method. It has been shown that by careful adjustment of the waveguide width, the slant sidewalls and the bending radius, a very compact polarization rotator design, only 60 μm long, with extremely low overall loss, and nearly 100% polarization conversion ratio can be achieved.