Dual-Parameter Sensing And Performance Analysis Based On Polarization-Maintaining Photonic Crystal Fiber Bragg Grating

Optical fiber sensors with the advantages of anti-electromagnetic interference,high sensitivity performance,fast response speed,wide dynamic range,small size and light weight,are one of the research hotspots in the field of optical communication.Special fibers and fiber gratings play an important role in fiber sensing with their unique characteristics.In this paper,a novel optical sensor based on polarization-maintaining photonic crystal fiber Bragg grating(PM-PCFBG)structure is designed and simulated which can realize simultaneous measurement of temperature and pressure.The sensitivity of the sensor under temperature change and pressure state is studied and analyzed.After analyzing and summary the effects of various geometrical parameters of PM-PCFBG on temperature and pressure sensing performance,an improved parameters optimizing direction that can increase the sensitivity is proposed.The main research achievements are summarized as follows:(1)The advantages and disadvantages of polarization-maintaining photonic crystal fiber and fiber Bragg gratings in the field of sensing are compared.The development of birefringent fiber gratings is studied,while the comprehensive advantages of PM-PCFBG sensors are analyzed,and the temperature and pressure dual-parameter sensing principle of PM-PCFBG is deduced.(2)Characteristics of PM-PCFBG are jointly simulated by COM SOL and MATLAB,realizing the dual-parameter sensing of temperature and pressure.According to the results,it can be seen that the reflection spectrum of PM-PCFBG will exhibit two resonance peaks due to the birefringence characteristics,of which the wavelength seperation between the two resonance peaks change with pressure.while the peak wavelengths follow both temperature and pressure.According to simulation calculations,the temperature sensitivity of PM-PCFBG is 11.26pm/?,while the sensitivities of X-direction,Y-direction and 45°-direction transverse pressure are 2.702pm/MPa,0.7338pm/MPa and 1.975pm/MPa,radial pressure and hydrostatic pressure sensitivities are 1.974 pm/MPa and 2 pm/MPa respectively.(3)An optimized scheme for improving the sensitivity of temperature and pressure by changing the structural parameters of PM-PCFBG is proposed.When changing the structural parameters of the fiber cross-section,the temperature sensitivity is basically unchanged,while the pressure sensitivity changes with the structural parameters.To increase the sensitivity of X-direction transverse pressure,the small hole pitch can be reduced and the large hole diameter can be increased.When the small hole pitch and large hole diameter are 4.2 ?m and 51?m,the sensitivity reaches 3.104 pm/MPa.To increase the sensitivity of Y-direction transverse pressure,the small hole diameter can be increased and the large hole diameter can be reduced.When the small hole diameter and large hole diameter are 2.8?m and 4?m,the sensitivity reaches 1.953pm/MPa.To increase the sensitivity of hydrostatic pressure,the large hole diameter can be increased,the small hole pich and the fiber diameter can be reduced,when the large hole diameter,small hole pich and fiber diameter are 5.2?m,4.2?m and 45?m.respectively,the sensitivity reaches 3.665pm/MPa.When changing the grating period,the sensitivity of temperature and pressure is directly proportional to the period.