Characteristic Analysis And Optimization Of Fused-taper Fiber Coupler

With the rapidly development of optical fiber communication,the requirements for various optical devices are getting higher and higher.As the most widely used optical passive device in optical fiber communication,optical fiber coupler plays an important role in optical fiber communication for better communication quality.There are many kinds of optical fiber couplers,and the process is diverse.The taper fiber coupler has become the most widely used optical fiber coupler due to its excellent performance.Coupled mode theory is the most important theory for the analysis of fiber optic couplers,which lays a theoretical foundation for the development of fiber couplers.With the development of computer technology,various numerical calculation methods have also been applied to the research of optical fiber couplers,providing more effective simulations for the research of optical fiber couplers.At present,the most studied fuser-type fiber couplers are the finite element method and beam propagation method.The finite element method has a huge advantage in analyzing mode field modes and is used to simulate coupler characteristics.The beam propagation method is relatively simple in terms of relative finite element method and has outstanding performance in the coupling of analog couplers.This paper simulates the fiber coupler based on the finite element simulation software COMSOL,and analyzes the coupling situation according to its mode field characteristics firstly.Then,the taper fiber coupler was simulated using the beam propagation simulation software Rsoft.The experiments were carried out by changing the parameters of the coupler,and the influence of the melting degree on the coupling ratio characteristics of the fuser-type fiber coupler was studied.The relationship between the additional loss and the coupling length of the fuser-type fiber coupler was also studied.Through simulation experiments,it is found that the splitting ratio and the melting degree of the fiber coupler are periodically related,the additional loss is related to the coupling length,and the length ratio in the melting zone of the taper cone is proposed to analyze the additional loss.Based on this research,it provides a great help for the production of fusion cone fiber coupler.