Study On The Crosstalk Characteristics Of Multi-core Fiber

With the development of information technology,the communication capacity is increasing day by day.Because of the advantages of large bandwidth,high speed and low loss,optical fiber communication has become the top priority of the future communication development.To construct a practical high speed and large capacity optical communication network,it is necessary to increase the effective mode field area,reduce the dispersion of fiber and increase the transmission capacity of optical fiber.In order to improve the capacity of optical fiber communication,space division multiplexing(SDM)technology is widely used in the fiber communication.By using multi-core fiber,SDM technology making the light into a plurality of core transmission fiber,greatly improves the communication capacity of the fiber,and also promotes the development of the optical fiber communication industry.Multi-core optical fiber is the basic device of optical fiber SDM system,which is related to the performance of the whole optical fiber communication system.In this paper,it makes a detailed research on multi-core fiber:1.Based on the coupled mode theory,the coupling equation of seven core fiber is deduced,and the coupling coefficient formula of the seven core fiber is obtained.In addition,the power coupling theory of optical fiber in long distance transmission is analyzed.According to the theory of power coupling,the paper studies that when light is inputting from different cores,what is the input power distribution of each core.2.The dispersion and effective mode field area of multi-core fiber are analyzed.The influence of the relative width of the trench,the relative refractive index difference of the trench and the relative position of the trench on the dispersion of the fiber,the effective mode field area are analyzed.The results show that the three parameters can keep the mode field area at a relatively high value.Meanwhile when the fiber core radius is a=5 ?m and the relative position of the trench(b/a)is less than 0.5,the dispersion of the fiber can be reduced to about-2 ps/(km-nm).and the mode field area of the core can be kept at about 145 ?m.3.The crosstalk of multi-core fiber is analyzed.The result shows that the moderating effect of crosstalk of the refractive index difference of trench is obviously better than the relative position of trench and the relative width of trench.When the core parameters of Atrench = 0.0025,b = 3 ?m and the relative width of trench(c/a)is greater than 1.2,the core crosstalk of the optical fiber can reach-50dB.