Analysis on the tunable optical properties of MOEMS filter based on Fabry-Perot Cavity

摘要

The phase shift on reflection from upper and bottom reflectors of the low interference order tunable Fabry-Perot MEMS filter was found playing a crucial role in the determination of resonant wavelength. The simple formula Δλ=2Δ(nd)/k, which was commonly used to describe the tuning process, was demonstrated not to be accurate. By using the transfer matrix method, the analytic expression for phase shift near the central wavelength of dielectric reflector was derived. The new linear relationship between the air gap and resonant wavelength was presented based on the resonant condition. The properties of mirrors that influence the tunable sensitivity were analyzed. Error of the linear relationship in a specified wavelength range was also estimated in this paper. The results are valid for all Fabry-Perot type optical tunable filters.