Sensing Properties Of Photonic Crystal Fiber Of Terahertz Wave

PCF is also known as Micro-structured optical Fiber or Holey Fiber. Since the periodic structure of refractive index of the PCF can control the motion of photons freely, it makes PCF possess many more attractive features than electron crystal materials. So it gives us a lot of room for designing and constructing, which makes PCF have obvious advantages in sensing and communication. The reaction of LC’s refractive index to the change of the external electric field is more sensitive than others, so we can infiltrate the air holes of PCF with LC selectively. Then we adjust the parameters of PCF by changing the voltage of applied electric field. PCF evanescent wave sensor design in biology-based and chemistry-based received widespread attention in particular. We used the finite element method to analyze and calculate its sensing capability. We provided a theoretical reference for corresponding theoretical study.This paper includes the following: The concept of the photonic crystals and photonic crystal fiber were introduced. The main features of photonic crystal fibers were introduced. So did the status of the PCF applications in sensors.The paper describes the classification and physical properties of LC, focusing on the optical properties of liquid crystals. We get the LC’s properties, data and the expression, which provides a reliable theoretical basis for the transmission theory of the PCF filled with LC.The calculation method using in the analysis of the PCF sensing properties. We focused on the finite element method because the software COMSOL is based on this method.We use COMSOL and MATLAB to do simulation of four different constructions. And we received the performance parameters of the PCF infiltrated by LC 5CB. We change the LC’s refractive index by changing the external electric field. These properties include effective refractive index, the normalized frequency, the effective core area, numerical aperture and waveguide dispersion. It provides references to design voltage sensing terahertz waveguide device used for corresponding demands.We proposed two kinds of twin-core PCF structures. We use software COMSOL to simulate two structures and use MATLAB to calculate and analyze the parameters we obtain. We achieved some sensing property of two structures, and the parameters changing with the incident wavelength. This type of evanescent wave sensor provides important theoretical basis for the evanescent wave sensors.