Research On Sensing Characteristic Of Photonic Crystal Fiber And Design Of Demodulation Scheme

Photonic crystal fiber(PCF)is applied to various fields extensively because of its unique structural design and novel characteristic of propagating light.Especially excellent characteristics in the field of sensing make PCF to be one of the hot research points at present stage.In this paper,the research comments of sensing characteristic of PCF as follows:(1)Based on the theory of transverse mode coupling in optical waveguide,a kind of magnetic fluid(MF)filled photonic crystal fiber structure is designed.The temperature/magnetic field sensing is realized by optimizing the structure.The temperature sensitivity coefficients are achieving 0.512nm/? and 0.449nm/?meanwhile the magnetic field sensitivity coefficients are achieving-1.927nm/m T and-1.681nm/m T.(2)Bsed on the principle of photonic crystal fiber Bragg Gate(PCFBG)temperature sensing,the temperature insensitive sensing characteristic is achieved by selectively filling propylene glycol into air-holes of PCFBG cladding.This temperature-insensitive PCFBG has excellent strain sensing characteristics.Therefore,the temperature/strain parametric sensing can be realized by the cascade structure and parameter optimization.The sensitivity coefficient of temperature compensation sensing channel is 1.226pm/??.Temperature sensitivity coefficient and strain sensitivity coefficient of another conventional sensing channel achieve 13.27pm/?and 1.203pm/??,respectively.(3)Based on the theoretical research results,a demodulation scheme of photonic crystal fiber grating sensing is designed.The scheme mainly includes optical path unit,signal processing unit and display unit,and the temperature/strain dual-parameters sensing is realized by software design.