| Temperature sensors are widely used in many fields such as agriculture, industry, Internet of things. Relying on its ultrahigh birefringence characteristics, polarization-maintaining photonic crystal fiber(PM-PCF) has become a research hotspot in optical fiber sensing technology. temperature sensor based on PM-PCF has some characteristics such as electric insulation, high pressure resistance, and corrosion resistance. PM-PCF is one of its important components. The sensitivity of the temperature sensor depends on the property of PM-PCF.A kind of hybrid lattice PM-PCF with modified circular and rectangular air holes is proposed in this paper. By using Comsol based on a finite-element method, fundamental mode field and properties of modal birefringence are investigated. The birefringence and beat-length of proposed PCF are also investigated with different parameters. Numerical results show that by introducing hybrid air holes, a heightened modal birefringence of the order of 10-2 has been obtained within the wavelength ranging from 0.4μm to 2.0μm in the proposed PM-PCF. The birefringence will be up to 3.4849×10-2 with parameters Λ=1μm, A=1μm×0.1μm, D=0.96μm at excitation wavelength λ=1550nm. Then the temperature sensitivity is discussed from three aspects: types of thermal fluid、filling modes and the change of structure parameters. Simulation results show that a heightened temperature sensitivity(10-5) has been obtained with alcohol filled in the circular air holes of fiber core area. Finally a temperature sensor with the alcohol-filled PM-PCF Sagnac interferometer is designed. Matlab simulation analysis show that through apparent transmission spectrum shifts, a sensitivity of 2nm/℃ is achieved with an incident light source of 1450nm-1650 nm. A large linearity measuring range of- 30℃-70℃ is also abtained. The temperature sensor has advantages of electromagnetic interference, high sensitivity, wide measurement range, and has extensive application in industrial detection and control. |
PDF Full Text Request