A silicon-based tunable optical filter designed for low power consumption and fast thermal modulation

A novel MEMS-based concept for tunable optical filters, essential components for monitoring and reconfiguration of optical wavelength-division multiplexing (WDM) networks, is presented. The device is based on a Fabry-Perot interferometer employing a silicon cavity and silicon-based dielectric Bragg mirrors and is fabricated as a freestanding membrane. Wavelength tuning is achieved through thermal modulation of the resonator´s optical thickness. The present concept features low power consumption and fast thermal modulation. Measurements of optical filter performance and tunability are presented. The thermal behavior of the heater configuration is compared with numerical simulation results. By varying the resonator-length of a Fabry-Perot etalon, the transmission wavelength may be tuned.