Modes Evolution And Transmission Analysis Of Single Mode Fiber Spherical Probes

Optical fiber connecting and coupling technology is the basis of optical communication systems.The construction of modern optical networks such as fiber-to-the-home systems and data centers require a large number of high quality optical fiber connections and couplings.Optical fiber probes are the core component of this requirement.The purpose of this paper is to investigate the evolution of modes and the transmission process of single mode fiber spherical probes,to establish a mode analysis theory for single mode fiber spherical probes,and to find out the evolution of modes in spherical probes with different radius of curvature.The factors affecting the light transmission of the spherical probe are obtained,which provides a reliable theoretical basis for the mass production of high quality fiber probes.This paper first establishes the theory of mode analysis for single mode fiber spherical probes.According to the structural characteristics of the spherical probes with longitudinal non-uniformity,a stepped cascade method for single mode fiber spherical probes is proposed,and model function models for the three-segment spherical probes are deduced.Based on the analytical solution of three-segment spherical probes obtained by Matlab,it is found that the fundamental mode of single mode fiber spherical probes changed.Then based on the improved eigenmode expansion method,the evolution of modes and their transmission process in single mode fiber spherical probes are simulated and analyzed in detail.It is found that the longitudinal non-uniformity of the spherical probe structure causes mode coupling,and the power,effective refractive index,and field distribution of modes all changed.The evolution rule of single mode fiber spherical probes mode with different curvature radius is basically the same.According to the distribution of the main high order modes in the front end of spherical probes,this paper proposes the concept of the single mode fiber spherical probes mode eco-environment.It is pointed out that the mode eco-environment is determined by the cylindrical probe symmetrical structure and the polarization state of the input field.Then,the simulation analysis of single mode fiber spherical probes optical wave transmission process shows that the superposition of the fundamental mode and high order modes causes the top field distribution of the spherical probes changed;the radius of curvature of the single mode fiber spherical probes are different,and the phase difference between modes are different as well.The transmission loss of the large curvature radius spherical probes is basically zero,and the small curvature radius spherical probes have slight transmission loss.In the end,the single mode fiber spherical probes and optical fiber patch cords based on spherical probes are experimentally tested and analyzed.According to the actual size of the sample,a simulation model is established,and the evolution rules of modes in the sample is analyzed.The conclusion is the same as the result of the previous mode analysis and simulation calculation.The three-dimensional morphology and insertion/return loss test of the optical fiber patch cords based on the single mode fiber spherical probes with large curvature radius prove that all the samples reach the A-level standard.