Characterization of Rayleigh backscattering arising in various two-mode fibers.

Dawei Yu,Chigo Okonkwo,Songnian Fu,Ian Giles,Ton Koonen,Zizheng Cao,Lei Deng,Ming Tang,Deming Liu

doi:10.1364/oe.24.012192

Abstract

We experimentally characterize the mode dependent characteristics of Rayleigh backscattering (RB) arising in various two-mode fibers (TMFs). With the help of an all-fiber photonic lantern, we are able to measure the RB power at individual modes. Consequently, mode dependent power distribution of RB light caused by arbitrary forward propagation mode superposition can be obtained. The total RB power of the TMFs under test is higher than that of single mode fiber by at least 2 dB over the C band. Meanwhile, the RB light occurs among all guided modes in the TMFs with specific power ratios. The experimental characterization agrees well with the theoretical calculations.

Highlights

As one of dominant linear characteristics of optical fibers, Rayleigh backscattering (RB) results from small scale inhomogeneities of the local electric susceptibility, which act as induced dipole oscillators [1, 2]
Mode dependent power distribution of RB light caused by arbitrary forward propagation mode superposition can be obtained
The RB light occurs among all guided modes in the two-mode fibers (TMFs) with specific power ratios

Summary

Introduction

As one of dominant linear characteristics of optical fibers, Rayleigh backscattering (RB) results from small scale inhomogeneities of the local electric susceptibility, which act as induced dipole oscillators [1, 2]. Many applications based on the RB arising in optical fibers have been widely explored, such as optical time domain reflectometry (OTDR) [3], optical fiber pipeline safety monitoring [4], distributed acoustic sensing [5] When it comes to fiber optical bi-directional transmission, RB becomes one of the dominant impairment sources [6,7,8,9]. The backscattering power and corresponding mode dependent power distribution, as well as the relationship with specific forward propagation mode in various kinds of FMFs, still need to be explored. The RB power ratio and the RMDP are found to be sensitive to the mode profile of forward propagation light Such two parameters are challenging to quantitatively characterize through experiment, due to the limitation of precisely selective mode excitation. As the development of mode division multiplexers, all-fiber photonic lantern (PL) [28, 29] makes the measurement of RB arising in the FMF much easier, if we can get the power transfer matrix of PL and successfully suppress the Fresnel reflection from the facet

Methods

Results

Conclusion