Manufacturing Technology For Optical Fiber Extrinsic Fabry-Perot Interferometer Sensor

Optical fiber extrinsic Fabry-Perot Interferometer(EFPI) sensor has a strong anti-electromagnetic interference capability andcan work stably for a long time in extremely harsh environments.It has broad application prospects in the fields of structural health monitoring, petrochemicalindustry, aerospace, military affairsetc. However, its existing manufacturing technology has problems of lack of precision of the core parameters, such as the initial length of F-Pcavity, gauge lengthetc. Soits measurement range, measurement accuracy, long-term reliability and other performanceindexesare also difficult to guarantee.Its application and promotion has been hampered due to the lack of commercial special equipment and mass production.Therefore, a targeted solution is proposed and a dedicated manufacturing instrument ofEFPI is designed and developed. The main contributions of the paper are as follows.The basic principle of strain sensing of EFPI is analyzed, and the manufacturing requirements of EFPIare put forward according to the above.The foundation of designing and developing the manufacturinginstrument is laid solidly.According to the structureof EFPIand existingproblems in manufacturing process, the overall design scheme and the modular structure of the instrument areput forward.The design offixture module, monitoring module, optical fiber mobile module, whole mobile module and fusion module are completed.Finally,the physicalinstrumentis successfully built up.According to the performance requirements and actual application needs, fusion parameters are also optimized throughcross test.Finally, making use of the special manufacturing equipment, 54 sensor samples are made under the condition of the optimized process parameters.The strain measurement range, strain transfer efficiency, sensitivity, linearity and long-term reliability of EFPI underthe manufacture instrument and optimal manufacturing parameters are assessed and evaluatedthrough real experiments.The results of the experiment of strain measurement range show thatwith tensile strain of 1400??applied on EFPIs, the yield rate of EFPIs reach 91%, the fluctuation of strain transfer efficiency does not exceed 10% and the sensitivity is about 13nm/??.The results of long term reliability experiment show that through acceleration ageing the survival rate of EFPIs is 100%, the sensitivity fluctuation is not more than 7%, the linearity is always maintained above 0.999 and spectrum of most EFPIs do not change significantly.All the performance indexes of EFPI meet the requirements of practical application.