Study On The Statistical Properties Of OAM-PMD In Ring Core Fiber

In recent years,a variety of new information technologies have been proposed,the development of these technologies requires higher communication capacity to guarantee,and the single-mode optical fiber transmission system whcih as the backbone network due to the nonlinear Shannon limit,will no longer meet the growing demand for communication capacity,it is urgent for us to develop new multiplexing technology to further improve the communication capacity.In the space multiplexing degree,which is not yet fully developed,the mode multiplexing technology based on the orbital angular momentum can greatly improve the transmission capacity of the optical fiber communication system because of itsoretically infinite multiplexing,this newly proposed multiplexing technology attracts a great deal of attention from researchers.But it will inevitably be affected by the OAM mode polarization mode dispersion when we use OAM mode multiplexing in optical fiber.Because OAM-PMD is randomly changed and difficult to compensate,it will seriously limit the transmission capacity and transmission distance of OAM mode multiplex transmission system.The study of its statistical characteristics can provide a basis for the design of OAM mode multiplex transmission system and OAM-PMD compensation.Therefore,this paper mainly studies the statistical properties of the first order and second OAM-PMD of OAM mode.The contents of research on OAM-PMD:(1)Based on the correlation study of the statistical characteristics of PMD in SMF,the statistical characteristics of first order OAM-PMD of OAM mode is deduced.Based on this,The effects of different degrees of elliptical birefringence or nonconcentric birefringence on the first order OAM-PMD coefficients of ring core fibers were studied.Besides,the Jones transmission matrix method is used to simulate the statistical characteristics of the first order OAM-PMD of the OAM mode,including the mean value,the root mean square and the statistical distribution.(2)The statistical properties of the second order OAM-PMD and its parallelcomponents and perpendicular components in the ring core fiber are theoretically derived,and the influence of the elliptical birefringence or nonconcentric birefringence of the ring core fiber on the second order OAM-PMD coefficients is simulated by using COMSOL and MATLAB software.