The Study Of Photoelastic Modulator And Its High-voltage Drive Technology

With the deepening and the rapid development of scientific research,high-performance Fourier Transform spectroscopy technology have a widerange of applications in the fields of safety, military, aerospace, and otherhigh-tech areas. Interferometer is the key part of the Fourier Transformspectrometer with its structural design quality affects the performance of theentire spectrometer. Photo-elastic based interferometer, consists primarily ofphotoelastic modulator and driver. Because the new static FTS (FourierTransform spectrometer), which based on photo-elastic based interferometer,has many advantages such as ultra-speed, high sensitivity, wide spectral rangeand vibration-proof. On the basis of analyzing the research status anddevelopment trend at home and abroad, this thesis makes studies of photoelasticmodulator and driver accorded with the requirement of project.In this paper, the first aspect is the study of the construction and the optimization of photoelastic modulator. First of all, structure and physicalproperties of ZnSe and piezoelectric quartz crystal that used in the photoelasticmodulator was analyzed theoretically. Secondly, the vibration mode and thefrequency characteristic of piezoelectric quartz crystal were studied. Then,according to the frequency requirements, the size of ZnSe and piezoelectricquartz crystal was calculated. A finite element analysis of ZnSe andpiezoelectric quartz crystal was made by multi-physics coupling analysissoftware（COMSOL Multiphysics）and the physical solutions were got with theresonant frequency and in the time domain. At last, the influence of temperatureon the natural frequency of modulator was analyzed and a dynamic model ofresonance frequency-temperature was built to provide important theoreticalbasis for temperature controlling and frequency tracking of the photoelasticmodulation system. The second aspect is the study of driven technology. In thispart, various components of the drive and its functions were analyzed and theinverse tandem photoelastic driven circuit was designed to improve optical pathdifference of the photoelastic modulator. Then, we make use of the circuit simulation tools toverified the simulation of single and inverse tandem circuit.Finally, a photoelastic modulator interference system was built in thelaboratory to test performance of the driver and the photoelastic modulator. Theresult of test shows that the resonant frequency of photoelastic modulator was50.018kHz and the maximum voltage of driver was1100V. Besides, with thephotoelastic modulator and the driver designed in this thesis, the spectralresolution can achieve44.3μm at voltage of300V and can even achieve162μm in theory. After experimental analysis and demonstration, the study ofphotoelastic modulator and its driver had been demonstrated in theoretically andpractically.