Study On The Photonic Crystal Fiber Transverse-stress Sensor Based On SPR Technology

Since the flexible control structure and unique light control mechanism,photonic crystal fiber(PCF)has been an excellent candidate for fiber sensing platform.Also,surface plasmon resonance technology has been widely applied in variety sensing fields for its high accuracy and high sensitivity.Primarily,this paper starts from the structure design of PCF,and combining with the surface plasmon resonance technology,different novel transverse-stress sensors based on PCF are designed.Through the in-depth analysis of sensing mechanism,this research provides a theoretical guidance for the application of novel transverse-stress sensor.The main contents of this paper are as follows:The research progress of transverse-stress sensing at home and abroad is reviewed,and the low sensitivity and cross sensitivity in transverse-stress sensing are expounded.The defects of the original transverse-stress sensing are solved through the optimized design of PCF structure,and the combination of ultra-large side-hole structure and SPR technology.A transverse-stress sensor with polarization filtering function based on specially designed PCF is proposed.Four ultra-large side-holes are introduced into the cladding layer,and two of them are gold-coated to enhance the stress sensitivity.The finite element method(FEM)is applied to study the polarization-dependent wavelength-selective sensing characteristics at the optical communication wavelength.Results reveal that the sensor can achieve a high sensitivity of transverse-stress in either direction.Combining the advantages of side-hole structure and SPR technology,the proposed sensor is believed to be an excellent candidate for the transverse-stress measurement.A transverse-stress sensor with enhanced sensitivity based on nematic liquid crystal(NLC)filled PCF is proposed.The central hole of the PCF is infiltrated with NLC material with an adjustable rotation angle to achieve the polarization-dependent wavelength-selective sensing.Results reveal that based on the polarization filter characteristic at special wavelengths,the sensor can achieve transverse-stress sensing with high sensitivity and no bending loss.Besides that,the transverse-stress and temperature in either direction can be effectively discriminated by adjusting the rotation angle of the NLC.