Thermally tunable optical thin-film filters with sub-nanometer resolution and 41.7 nm continuous tuning range

A MEMS-based, tunable optical filter with a transmission linewidth of 0.28 nm, continuously tu nable over a spectral range of 41.7 nm, is presented. The thin film interference filter employs a solid-state silicon cavity and silicon-based distributed Bragg reflectors (DBR). Tuning is achieved by varying the optical resonator thickness through thermal modulation. The filter is configured as a membrane and operates up to a temperature of 450 °C. Such a filter is essential for monitoring and reconfiguration of optical data communication networks and is also applicable for gas sensing.