Effect of mirror curvature in MEMS micro-mirror based wavelength-selective switches

The effect of mirror curvature has been studied for its influences on the operation of the wavelength-selective switches. Expressions for the curvature-induced losses and path length differences are developed. The study shows that curvature gives rise to a fixed dispersion, which matches experimental observations. In addition, it is demonstrated that mirror curvature is responsible for passband tilt in the attenuated state with DD tilt mirrors. Finally, mirror curvature can be used advantageously to create a channelized dispersion compensator.