Development Of A Tunable F-P Filter Driven By Piezoelectric Ceramic Micro-shifter

With the development of the designing, fabricating technology, the tunable FP filteris more and more widely used in the spectral analysis, particularly in hyperspectralimaging. In this paper, a FP tunable filter system driven by piezoelectric ceramicmicro-displacement which is controlled by Digital Signal Processing(DSP) unit isdesigned. Combined with the Bragg membrane system,3~5μm band optical filter isobtained. The testing and verification work of the system have been done by using theMichelson interferometer. Results show that this system has an optical filtering capability,and also the design of the piezoelectric ceramic actuator is correct, the drive control circuitand the membrane system performance is proved. The research contents were listed asfollows:(1) The system general architecture of a tunable FP filter was described. Theoperating mechanism, both the load characteristics of the system and the relationshipbetween voltage and output displacement of the displacement amplification mechanism isanalyzed.(2) The system driven circuit was designed, including the control circuit module andthe high voltage amplifier module based on DSP and PA12A respectively.(3) Antireflection coatings and high reflective thin films in3~5μm band weredesigned, with the software TFCalc, transmittance characteristics of the device, thescanning features and the influence of the incident angle on the device performance wereanalyzed.(4) The system was built based on the design of the mechanical structure and thedrive circuit. The output voltage characteristic of the drive circuit was tested first, and then,by using Michelson interferometer, both the relationship between drive circuit and outputdisplacement and the mechanical properties of the filter system were tested, issues of the system were analyzed and the feasible improvement is given. Finally, the performance ofa F-P filter with2μm cavity length, Bragg reflector film, antireflective film was tested in3~5μm band by using Fourier transform infrared spectroscopy.