Research On Miniature Infrared Fabry-Perot Filter Cavity

Micro Fabry-Perot tunable filter based on MEMS technology will be widely usedin the area of micro Spectrometers and DWDM optical communication system.Compared with other tunable filters, it has the advantages of small volume, easy tointegrate with lasers, detectors or modulators, large tunable spectral range, high spectralresolution.This paper presents the research of this filte,we have proposed a new MEMSFabry-Perot filter structure combining with grating and Fabry-Perot cavity. Thisfilter can not only ensure a wide free spectral range, but a narrow FWHM. In this paper,we attempts to deeply analyze the implementation mechanism, the parameters selectionand the structure of the Fabry-Perot filter. The main contents are as follow:(1)Review state-of-the-art of the micro Fabry-Perot and analyze the reason of theirpoor-performance; Propose the new structure based on modulator composed of gratingand Fabry-Perot filter, which can effectively improve the spectral resolution with widefree spectral range.(2)Analyze the principle of new Fabry-Perot filter and discuss their opticalcharacteristics of the core component.(3)The author has chosen one micro Fabry-Perot bridge structurefrom several common designs. The driving performance of this micro bridge structure,as well as the parallelism and stability of the device is simulated by using IntelliSuitanalysis. By choosing different thickness of the micro-bridge deck, i.e.0.5μm,0.6μm,0.7μm,0.8μm,0.9μm,1μm, and comparing with the flatness of micro-bridge withinelectrostatic interactions, we found that when the thickness is1μm and the voltage is5V,the tilt displacement of the upper-mirror is9.11nm and the maximum cavity lengthchange is242nm.(4) Introduce Fabry-Perot filter needed processing technology in detail, such aslithography, deposit, etching, Surface micromachining technology etc. Analysis some of the problems which may occur in the procession, such as thin film stress control, therelease of the sacrificial layer. To solve these problems we give the correspondingsolution. At last, utilize surface micromachining technology, exploratory propose thefilter fabrication processes.