Research On The Sensitizing Technology For Optical Accelerometer Based On The Structure Of Multiple Reflection

It is difficult to effectively improve the phase sensitivity and maintain the same work frequency range as while for fiber-optic accelerometer because of the constraint relationship between phase sensitivity and resonant frequency. The miniaturization requirement was proposed in some key areas of measurement for accelerometer in recently years, and F-P cavity accelerometer based on MEMS technology is currently one of the hot topics in the research on miniaturization. Since the existed structural sensitivity enhancement measures play little role in sensitivity- frequency constraint improving, it is necessary to seek a new kind of sensitivity enhancement technology.The sensitivity- frequency constraint is obtained based on the performance analysis of the beam structure accelerometer, and the sensitivity- frequency constraint constant of the accelerometer for the elastic cylinder structure is calculated. A is proposed. The optical parameters and the mechanical parameters which could affect the sensor’s performance are discussed in detail respectively. Series of experiments utilizing one-dimensional optical accelerometer are carried out to investigate the theoretical results. The test results show that the multiple-reflection scheme would be a helpful means for the sensitivity enhancement of micro- machined miniature F-P cavity accelerometer.The main results of dissertation are as follows:1. The sensitivity- frequency-constraint is proposed through analyzing the performance of the beam-structural accelerometer, and the relationship between the performance of the accelerometer and the mechanical parameters is simulated. The analytical results can be used to design the accelerometers based on the multiple-reflection sensitivity enhancement scheme.2. A new optical fiber accelerometer structure based on the multiple reflective spatial lights is proposed in this article. Cylindrical mod el was used to analyze the performance of the structure. The results show that the sensitivity can be improved effectively by increasing the reflective times while the resonant frequency is unchanged, and the increases of the phase sensitivity is proportional to the reflective times.3. According to the theoretical analysis results, accelerometers with 1 times, 10 times and 11 times reflection are developed, and the acceleration sensitivities and frequency responses of the sensors are measured. The experime ntal results show that the phase sensitivity of the accelerometer with different reflective times fixed with a push-pull structure were-7~-5dB, 12~14dB and 13~15dB re 1rad/g in the range of 80~800Hz respectively, and the frequencies of the accelerometers are uniformly around 1700 Hz. The results indicate that the acceleration sensitivity can be effectively improved by increasing the reflective times while obtain the same resonant frequency.