Systematic design of microprism-type low-loss step-index bent waveguides

By taking into account the curved travel path instead of the conventional abrupt optical line path in the bent region of three-dimensional embedded structures, we propose two kinds of microprism-type waveguide bends and systematically derive precise phase compensation formulas. The simulation results obtained with the fast Fourier-transform beam propagation method indicate that the normalized transmitted powers are greater than 95% even though the bent angle is as large as 10 degrees .