Design of MDM channel precision positioning scheme at the end of a few-mode optical fiber with enlarged core diameter

摘要

This work presents method for design of precision positioning scheme for mode division multiplexing (MDM) system channels at the end of link few-mode optical fiber with enlarged core diameter. Proposed solution is based on combination of well known overlap integral method and earlier on developed Gaussian approximation modification generalized for analysis of silica weakly guiding optical fibers with one outer solid cladding and arbitrary axially-symmetric refractive index profile. The last one provides a passage to analytical expressions for any order mode coupling coefficients under taking into account set precision radial misalignment. By using presented method we computed launching parameters of 5-mode MDM multiplexer channels to the end of few-mode optical fiber samples with enlarged core diameter up to 42 μm and reduced differential mode delay provided by specially designed graded refractive index profile. According to computation results, it is able to transmit the almost total one MDM channel mode power to only one optical fiber particular mode with the same azimuthal order by corresponding combination between mode field diameter and precision radial misalignment.