Influence of etching slope on two-dimensional photonic crystal slab resonators

Abstract

The influence of the etching slope on the Q-factors in two-dimensional (2D) photonic crystal (PhC) slab resonators is studied. The Q-factor of a three-lattice-long modified linear resonator was measured to be much smaller than the theoretical prediction. Through a finite-difference time-domain (FDTD) simulation, we confirmed that the Q-factor decreases with etching slope. The horizontal loss becomes dominant when the angle of the etching slope exceeds one degree. This loss originates from the coupling into propagating TM-like modes.