Development Of Fiber-Optic Acoustic Sensor And Research On Its Denoising Algorithms

Fiber-optic Acoustic Sensor has many advantages,including flexibility,small size,anti-electromagnetic interference and so on,which makes it more widely used in the specific situation where electronic microphones can not be used.Also,it plays an irreplaceable role in security,national defense and other fields.Fiber-optic Acoustic Sensor is a kind of sensor that senses the change of external sound pressure and affects the intensity and phase of light.By detecting such factors,the target sound can be identified.Therefore,the sensitivity of the probe of the Fiber-optic Acoustic Sensor plays a decisive role in the whole system.Because the whole system is designed in an all-optical structure,and it has certain noise.With the increase of sensitivity,the background noise detected will also increase.How to enhance the de-noising of the detected speech signal also affects the application of the sensor.This paper focuses on several important factors affecting the performance and application of Fiber-optic Acoustic Sensor.It mainly involves the research and preparation of the probe of the Fiber-optic Acoustic Sensor based on MEMS,and the research and software implementation of the speech signal processing algorithm.The main contents are as follows:1.In view of the probe sensitivity of the Fiber-optic Acoustic Sensor,a detailed theoretical analysis is carried out.The content includs stress analysis,vibration analysis and spectral analysis.Besides,the factors affecting the probe sensitivity of the sensor are obtained,and the theoretical fundation for the development of a better probe is made.2.Put forward the probe of the Fiber-optic Acoustic Sensor.Based on the analysis of the influencing factors,the fiber-optic probe is designed and fabricated.The response and sensitivity of the probe are tested by experiments,and the common spectrum of the probe is analyzed.The developed fiber-optic probe can detect the weak sound signal,and it has completedly equipped probe to protec the device.3.Wavelet Wiener filtering algorithm is proposed to denoise and enhance the acquisition signal of the Fiber-optic Acoustic Sensor in MEMS.The software development of the algorithm is carried out.By testing the software based on the algorithm,it is found that the speech processing system can enhance the sound signal denoising.Moreover,it has good performance.4.A large number of practical engineering tests have been carried out for the developed Fiber-optic Acoustic Sensor,so that complete test data have been obtained.The results show that the developed Fiber-optic Acoustic Sensor System has good performance and consistency with the signal collected by the electronic microphone.The obtained engineering data pave the way for further improvement and optimization of the equipment.The above work has passed the practical engineering application test.It means that the theory can be applicated by the remote detection of speech signals,and can be used to solve the major problems in the field of national defense,security and so on.