Research On The Stability Of Quadrature Point Of Fiber Fabry-Perot Sensor

With the progress of modern science,the optical fiber sensors can be applied more and more places,which has become an inseparable part of the development of modern science and technology,and occupies a replace position in getting information.The Optical fiber sensor has the advantages of high resolution,strong ability of anti-electromagnetic interference,high sensitivity,high temperature resistance,small volume,light weight,large dynamic range,strong stability,simple structure,it can adapt to a variety of complex environments.The fiber optic sensors can not be replaced because of their own advantages,which will play more and more important role in the future development.The Fabry-Perot(F-P)sensor is an important one among many sensors.Now,the F-P sensor gets a wide range of results for its research,but its operating point changes with the temperature environment,which will affect the measurement sensitivity and data accuracy.In this paper,we mainly study the influence factors of the operating point change of the F-P sensor and the relationship between the cavity length and the wave length,which makes the whole system quadrature point(Q-point)stable.The research contents are as follows:1.Analyze the theory of F-P sensor.According to this formula,we can know the influence of the factors change of the cavity length and wave length on the reflected light intensity,and simulate the influence factors of reflected light intensity.From the simulation results,we learn that when the cavity length becomes longer the wave length also becomes longer in order to stabilize the Q-point,which provides a theoretical basis for the realization of the whole system.2.Construct the whole F-P sensing system detection and Q-point stabilization system circuit.Design the F-P fiber optic sensing and detecting system based on the weak signal detection technology,to achieve the high-precision F-P fiber amplitude demodulation system through design part circuit of laser light source,amplify the lock,and AD collect and control circuit;Design the system of Q-point stabilization system based on the negative feedback,the F-P optical fiber sensing system is achieved by combining the laser light source temperature control circuit system and the Q-point voltage acquisition and the negative feedback.At last,collect and store and display the F-P sensing system data through the preparation of the PC software,which is to build a complete and stable F-P optical fiber sensing detection system.3.Verify the correctness,stability,and reliability of the Q point stabilization system of the F-P optical fiber sensing system by simulation experiments.Verify the correctness of the Q point stabilization system of the F-P optical fiber sensing system by adjust the temperatureof the temperature table to make the cavity length of F-P fiber sensing system slightly changed.Verify the stability and reliability of the Q point stabilization system of the F-P optical fiber sensing system by the fixed audio vibrating the signal the sensing unit of the F-P fiber sensing system,the weak signal detection of the F-P sensor,and the high precision detection and collection of the weak vibration signal.