Optical filters capable of single control parameter based wide tuning are implemented and studied.A prototype surface micromachined 1 3μm Si based MOEMS (micro opto electro mechanical systems) tunable filter exhibits a continuous and large tuning range of 90nm at 50V tuning voltage.The filter can be integrated with Si based photodetector in a low cost component for coarse wavelength division multiplexing systems operating in the 1 3μm band.
A 1.55μm Fabry-Perot (F-P) thermo-optical t unable filter is fabricated.The cavity is made of amorphous silicon (a-Si) layer grown by electron-beam evaporation technique.Due to the excellent thermo-optical property of a-Si,the refractive index of the F-P cavity will be changed by heating;the transmittance resonant peak will therefore shift substantially.The measured tuning rang is 12nm, FWHM (full-width-at-half-maximum) of the transmissi on peak is 9nm,and heating efficiency is 0.1K/mW.The large FWHM is mainly due to th e non-ideal coating deposition and mirror undulation.Possible improvements to increase the efficiency of heating are suggested.
