Study On Polarization Device Characteristics Of Gold-filled Photonic Crystal Fibers

Photonic crystal fiber has been favored by researchers in this field for its special light transmission modes,various excellent characteristics and adjustable internal structure,and has become a research hotspot.Nowadays,the popularity of the Internet and the rapid development of communication technologies have enabled globalization in many fields.As an important part of systems such as optical communication and sensing,the role of polarizing devices with excellent characteristics is becoming more and more important.This has prompted a large number of researchers to conduct a comprehensive study on photonic crystal fibers in order to obtain better characteristics,better performance,easier drawing,wider application of polarizing devices,and finally meet market demand,which has great significance for promoting the development of fiber industry.There are two main ways to improve the performance of photonic crystal fibers.One is to change the internal structure of the photonic crystal fiber,and the other is to fill the air hole with suitable material.Based on the full vector finite element method,and combining the two methods,the characteristics of polarizing devices based on photonic crystal fibers are studied.Several polarization device structures are designed and applied to beam splitters and filters respectively.The main research contents are as follows:A polarization beam splitter structure with ultra-short length and ultra-wide bandwidth is designed.By introducing an elliptical structure to increase the asymmetry factor and the symmetric metal-filled hole to form a high-order defect mode and resonantly couple with the core mode.Using the finite element method,the structural parameters are changed to analyze the transmission characteristics of the fiber,and finally obtains the optimal combination of parameters with excellent beam splitting characteristics.A porous core is introduced into the ordinary hexagonal photonic crystal fiber structure,and a certain thickness of gold film is coated in an air hole in the y-axis direction.Three different types of porous are analyzed by numerical simulation.The mode field distribution of the core PCF structure is studied,and the influence of the filling parameter variation on the filtering characteristics is studied for one type of structure.A novel hourglass structure was designed,and three different sizes of pores were introduced to increase the asymmetry factor and birefringence.At the same time,the addition of Au-coated pores brought the plasmon resonance effect of the metal surface,by changing the structural parameters and the filling parameters are numerically simulated and analyzed for the characteristics of the photonic crystal fiber,and finally two sets of optimal parameters are obtained.This combination can achieve the filtering effect on the communication wavelengths of 1.55?m and 1.31?m respectively,and the filtering effect is remarkable.In this paper,the asymmetry factor and the Au-coated material are added to the structural design to optimize the performance of the photonic crystal fiber,and finally the fiber structure with excellent performance is obtained.These research contents have a certain degree of theoretical guidance and reference significance for the fiber fabrication,fiber sensor and the application in the field of optical communication.