Design of wide-angle low-loss waveguide bends using phase-compensated effective microprism

A phase-compensated waveguide is designed on the basis of an effective microprism for wide-bending-angle and low-loss planar lightwave circuit applications. The microprism can be realized using a two-dimensional air-hole photonic crystal (PhQ structure with a hexagonal lattice, which is operated in the conduction band of the low-frequency region. By monolithically integrating the effective microprism in the bending area of an optical waveguide, its wavefront of eigenmode can be tilted to suppress the radiation loss occurring during the bending process. In order to demonstrate the feasibility of the proposed microprism for low-index-contrast waveguides, an example of a bent waveguide with the eigenmode nearly compatible to the single-mode fiber is adopted to develop the PhC microprism. The transmission efficiency of the designed bent waveguide with a bending angle of 12.96 degrees and a bending radius of 89.09 pm is optimized to be over 92% in the wavelength window of 14001600nm.