Time-dependence of the transmission matrix of a specialty few-mode fiber

J Yammine,E R Andresen,L Bigot,A Tandjè,Michel Dossou

doi:10.1063/1.5047578

J Yammine, E R Andresen + Show 3 more

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https://doi.org/10.1063/1.5047578

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Journal: APL Photonics	Publication Date: Dec 19, 2018
Citations: 6	License type: cc-by

Affiliation: University of Lille, Université d'Abomey-Calavi

Abstract

We report a time-resolved measurement of the full transmission matrix (TM) of a short length of specialty annular-core few-mode fiber which guides 10 vector modes. We show how our method can isolate the fiber TM from “misalignment” contributions from optics upstream and downstream of the fiber. From measurements spanning two days, we extract the drift of the fiber TM. We show that drifts in the TM elements are mostly described as correlated phase variations rather than amplitude variations. We show that an empirical model of the fiber TM parametrized in one parameter can successfully account for the drift.

Highlights

The utilized capacity of the world’s singlemode fiber (SMF)-based communication networks is nearing their physical limits.1 Spatial division multiplexing (SDM) based on multi-core fibers (MCFs) or mode division multiplexing (MDM) based on few-mode fibers (FMFs) has the potential for increased capacity.2–4In the simplest approximation, a MCF with N cores is thought of as N independent parallel channels, each being the equivalent of a SMF
The measured fiber transmission matrix (TM) can be transformed into any basis, and we refer to Appendix B where we present measured fiber TMs in other bases
We acquired a stack of 11 fiber TMs over a time span of 36 h

Summary

Introduction

A MCF with N cores is thought of as N independent parallel channels, each being the equivalent of a SMF. The interaction of two cores is governed by coupled-mode theory, so the cross talk is a function of, among others, the effective index differences between the cores which, in turn, are quite sensitive to strain and temperature which must be expected to vary as a function of both distance and time. Experimental measurements show that the inter-core cross talk can vary over time by as much as 10 dB.. The consequences for the design of MCF-based networks are important—the variability of the inter-core cross talk must be known in order to design a MCF network that can assure a certain minimum performance in all conditions. Channel models for MCF have been proposed in order to provide tools to assist in designing MCF networks.

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