| Fiber optical microphone, as a fiber optic sensing technology, with features like small and simple structure, high sensitivity, anti-electromagnetic interference, low-loss in optical fiber, corrosion resistance, safety and reliability, has a broad application prospects in monitoring and security field. A fiber microphone based on light intensity modulation is designed, The details are as follows:The first chapter introduces the fiber optical sensing technology and the characteristics of a variety of microphones, and the unique advantages of fiber optic microphone and research status are described.The second chapter describes the three major modulation fiber-optic microphone has used, and a variety of fiber-optic modulation structure that have been reported in paper, and fiber optic microphone performance standards are described.The third chapter describes the fiber optic microphone‘s design based on light intensity modulation, and simulated the core part of the microphone : a sound-sensitive membrane and a reflective film. The simulation results show that the designed fiber-optical microphone’s frequency response and Intensity response are to meet the application requirements.The fourth chapter is making and testing of fiber optic microphone. Test results show that the developed fiber optic microphones have wide frequency response, high sensitivity and high linearity response. After the signal was demodulated through the system, sound can be clearly heard.The fifth chapter is the engineering application of fiber optical microphone detection system. Through the tests in the substation, the system can meet the real-time monitoring of its perimeter sound.The final chapter summarizes the full text, make analyzes of current problems and solutions to the fiber-optic microphone, and pointed out the direction for further research. |
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