ANALYSIS OF INTEGRATED OPTICAL CORNER REFLECTORS USING A FINITE-DIFFERENCE BEAM PROPAGATION METHOD

Integrated optical corner reflectors in III-V semiconductors are analyzed employing a finite-difference beam propagation method and propagating the beam in parallel with the etched semiconductor-air interface. For this choice of propagation direction, the effects of mirror roughness, rotation, and displacement of the mirror surface from its ideal position can be assessed very easily. The integrated reflector whose mode size is larger shows less dependence on the mirror displacement error. The loss due to mirror surface roughness depends weakly on the mode size and strongly on the mode polarization, being larger for the quasi-TE polarization. The loss due to rotational errors of the mirror surface is not a strong function of polarization, but increases as the waveguide width increases. However, for a rotation error smaller than 0.1-degrees, which should be achieved easily, the excess loss is smaller than 0.2 dB at 1.3-mu-m regardless of the waveguide width.