Research On Loss Mechanism And Lapping & Polishing Process For Optical Fiber Connectors

The tremendous development of optical fiber communication needs higher performance of optical fiber connector(OFC).Insertion loss and return loss are the important parameters to evaluate the performance of OFC.To make clear the affecting factors of insertion loss and return loss has great significance for the improvement of the performance of OFC and the transmission quality of optical fiber communication system.To address the problems about manufacturing process of OFC,the connecting losses and contact of the ferrule and the lapping & polishing process for end-faces of OFC were investigated by theoretical analysis,finite element analysis and experimental study.Firstly,based on the analytic formula of insertion loss of single mode fiber derived by the theory of mode coupling,the analytic formula of return loss was derived by mirror method.The insertion loss and return loss of physical contact connector(PC)and angle physical contact connector(APC)under the different influence factors were analyzed.Secondly,the contact deformation of ferrules was simulated by finite element software ABAQUS.The result shows that the contact force provided by spring of OFC plays an important role in compensation for the optical end-faces with air-gap caused by optical fiber undercut.The formula between contact force and geometry parameters of ferrule was fitted based on the change of simulation parameters.Because the contact area of ferrule is around the optical fiber,the formula between contact force and geometry parameters of ferrule is irrelevant to the outside diameter of ferrule.The contact force provided by spring not only compensate air-gap but also possess certain effect on controlling the contact pressure between ferrules and improving contact stability.Excessive contact force can change the refractive index of optical fiber.Based on the result of finite element simulation,the insertion loss and return loss caused by the change of refractive index was calculated by using the thin film matrix method.The result shows that the change of refractive index caused by contact force has little influence on the insertion loss and return loss of OFC.For convenience of calculations,the contact force and geometry parameters calculation software was written by MATLAB GUI software based on the study results.In order to verify the simulation result,the change of insertion loss and return loss caused by contact force is measured by using fiber Bragg grating method.Finally,to improve the lapping and polishing process of OFC,the change of the geometry parameters caused by the abrasive particle size,the duration of grinding and the pressure of grinding are researched.The result provides reference for production process improvement of OFC.