Exact Model for Mode-Dependent Gains and Losses in Multimode Fiber

TL;DR

This paper develops an exact analytical model for mode-dependent gains and losses in multimode fibers under strong mode coupling, accurately describing the statistical properties of MDL for various fiber configurations.

Contribution

It extends existing models to large MDL regimes, showing MDL's eigenvalues follow the same statistics as the sum of a Gaussian and a deterministic matrix.

Findings

Model matches numerical simulations for different mode counts.

Eigenvalues of MDL follow the sum of Gaussian and deterministic matrix statistics.

Analytical results are valid for both two-mode and multi-mode fibers.

Abstract

In the strong mode coupling regime, the model for mode-dependent gains and losses (collectively referred as MDL) of a multimode fiber is extended to the region with large MDL. The MDL is found to have the same statistical properties as the eigenvalues of the summation of two matrices. The first matrix is a random Gaussian matrix with standard deviation proportional to the accumulated MDL. The other matrix is a deterministic matrix with uniform eigenvalues proportional to the square of the accumulated MDL. The results are analytically correct for fibers with two or large number of modes, and also numerically verified for other cases.