Research On Multi-core Optical Fiber Assisted By Multi-grooves And Air Hole

With the rapid development of modern Internet and information technology,People’s requirement for data transmission capacity is increasing day by day.The transmission capacity of traditional single-mode single-core optical fiber is getting closer and closer to Shannon limit,nowadays,the capacity and bandwidth of optical communication system are required to be higher.Multi-core optical fiber based on space division multiplexing can make full use of space dimension,which can effectively solve the limit of traditional optical fiber transmission capacity approaching the theoretical limit,and greatly increase the transmission capacity of optical fiber communication.However,there are many problems in multi-core fiber,such as the inevitable crosstalk between cores.Aiming at the characteristics of intercore crosstalk,mode field area and differential mode delay of multi-core fiber,in order to reduce intercore crosstalk and obtain large mode field area and low differential mode delay,the influence of structural parameters of multi-core fiber on the above-mentioned characteristics is deeply studied,and a multi-channel and air-hole assisted six-core fiber is proposed.The main research work is as follows:1.Based on the basic theory of electromagnetic field,electromagnetic wave and optical fiber transmission,the important transmission characteristics of multi-core optical fiber（including crosstalk between cores,mode field area,differential mode delay,etc.）are studied,and the theoretical model of multi-core optical fiber is constructed,this study provides a theoretical basis for the full text.2.By simulation,the effects of refractive index difference of core and cladding,core radius and auxiliary structure on crosstalk,mode field area and differential mode delay of conventional multi-core fiber are studied,it lays a foundation for the research and development of multi-groove and air-hole assisted six-core fiber.3.In order to reduce crosstalk between cores and maximize large mode area and low differential mode delay,a multi-channel and air hole assisted six-core fiber structure is proposed,the fiber is surrounded by three low-index grooves for each core,and a small number of air holes are added between adjacent cores in the way of groove-assisted and air-hole-assisted.According to the theory of light wave propagation and the structure of the fiber,the mathematical model of the fiber is studied.4.Through numerical calculation and analysis,the influence of structure parameters on crosstalk and mode field area characteristics of multi-channel and air-hole assisted six-core fiber in single-mode transmission is studied in detail,according to the calculation results and a lot of measurements,three groups of fiber structure parameters are obtained,which make the fiber performance reach a higher level.At the wavelength of 1550nm,the crosstalk between cores can reach-67.667d B,and the mode field area can reach282.087μm².In addition,the differential mode delay characteristics of the above three groups of fiber structures are studied under the condition of low crosstalk and large mode field area in two-mode transmission.The results show that the differential mode delay is less than 34ps/m in the S+C+L（1460nm-1610nm）communication band,the minimum is28.501ps/m,low differential mode delay can be achieved,and the effective mode refractive index difference of Mode LP₀₁and Mode LP₁₁is greater than 0.001,so the mode crosstalk is negligible.Finally,the performance of the proposed multi-channel and air-hole assisted six-core fiber is analyzed and summarized.