High Birefringence Properties Of Photonic Crystal Fiber And Its Application

Compared with the traditional fiber,photonic crystal fiber has many unique properties,such as infinite single mode transmission,high birefringence,high nonlinearity,large mode field area and other characteristics.Because of its excellent optical properties and flexibility in the design of the structure,since in 1992 put forward by P.St.J.Russell et al.,the application of optical communications,optical sensing and other areas of the subject has been extensive attention.We can flexibly design the structure of photonic crystal fiber,so as to obtain high birefringence characteristics of PCF,in recent years have been more and more studies on the characteristics and applications of photonic crystal fibers.In this paper,the birefringence characteristics of photonic crystal fiber are studied,and a new type of photonic crystal structure is designed.Based on the finite element method,the high birefringence of the optical fiber is realized by adjusting the structural parameters of the optical fiber and changing the background material.At the same time,it is analyzed that the birefringence of PCF is improved with the temperature change in the high birefringence of PCF when filled sensitivity liquid in air holes,the temperature sensitivity of PCF can be used for high sensitivity PCF temperature sensor.The main contents of this paper are as follows:(1)A new type of octagonal photonic crystal fiber is designed for the problem that the birefringence coefficient of the conventional circular air hole photonic crystal fiber(PCF)is not large,the elliptical air hole is difficult and the cost is high.By introducing an elliptical microstructure into the core region,the asymmetry of the fiber pattern is caused,and a high birefringence is obtained.The results show that the birefringence is as high as 4.026 × 10-2 at the wavelength of 1.55?m by setting the appropriate structural parameters,reaching the same type of elliptical air hole PCF,and the fiber is also obtained high nonlinearity coefficient in the X and Y directions,respectively,62.2W-1 ? km-1 and 43.7W-1 ? km-1.(2)A high birefringence photonic crystal fiber based on sulfur glass is designed.The fiber can obtain high birefringence in the order of 10-1,and obtain high nonlinear coefficient and low limiting loss,Nonlinear optical and supercontinuum generation,and so on.(3)In this paper,the temperature-sensitive properties of PCF are affected by the temperature-selective liquid filling in the air hole of PCF,a kind of high temperature sensitivity photonic crystal fiber is proposed.The thermo-sensitive properties of the photonic crystal fiber were studied from the two aspects:the selection of thermos sensitive liquid and the change of fiber structure parameters,the research results show that when the air holes are filled with ethanol,the thermos sensitivity of the PCF at excitation wavelength 1.55?m is 3.37×10-5?-1,and has wide application value in PCF temperature sensor.