Frequency scanned phase sensitive optical time-domain reflectometry interrogation in multimode optical fibers

K Markiewicz,T Nasilowski,M Napierala,Z Yang,L Thévenaz,K Wilczynski,J Kaczorowski,A Dominguez-Lopez,L Szostkiewicz

doi:10.1063/1.5138728

Abstract

Standard multimode optical fibers normally support transmission over some 100 modes. Large differences in the propagation constant and the spatial distribution of distinct modes degrade the performance of phase-sensitive optical time-domain reflectometry measurements. In this work, we present a new realization of a coherent time-domain interrogation technique using single-mode operation in multimode fibers. We demonstrate effectively distributed strain sensing on three different multimode optical fibers. Up to 4 km of multimode fiber has been correctly interrogated, featuring a spatial resolution of 20 cm.

Highlights

Distributed optical fiber sensors (DOFS) based on Raman, Brillouin, or Rayleigh scattering become ubiquitous in situations where the measurement of physical quantities, such as vibration, strain, or temperature, induced by multiple events over long distances is required.1–6 Research on DOFS based on Rayleigh scattering has naturally focused on single-mode fibers due to the absence of intermodal effects
We report on direct strain measurements using phase-sensitive optical time-domain reflectometry [φ-OTDR] based on single-mode operation in several few and multimode optical fibers
An single-mode fiber (SMF) was characterized without a higher-order mode filter (HOMF) to verify the performance of the measurement setup in a known situation

Summary

Introduction

Distributed optical fiber sensors (DOFS) based on Raman, Brillouin, or Rayleigh scattering become ubiquitous in situations where the measurement of physical quantities, such as vibration, strain, or temperature, induced by multiple events over long distances is required.1–6 Research on DOFS based on Rayleigh scattering has naturally focused on single-mode fibers due to the absence of intermodal effects. Coherent techniques based on Rayleigh scattering, in which the phase of the scattered signal is analyzed, need a more sophisticated setup when the fiber under test is multimode rather than single-mode.

Results

Conclusion