Hybrid Brillouin/Rayleigh sensor for multiparameter measurements in optical fibers

Abstract

We present a hybrid Brillouin/Rayleigh sensor for multiparameter sensing in optical fibers. The system makes use of a single laser pulse to excite both Rayleigh and Brillouin backscattering in the same optical fiber. In the detection path, the backscattered signals are separated based on their different wavelengths. The system is capable of determining simultaneously the Brillouin frequency shift (BFS) of the fiber, as well as the frequency contents of any vibration acting on the same fiber as recovered by phase sensitive OTDR (ϕ-OTDR) measurements. The reported experiments show the possibility to perform simultaneous temperature and vibration measurements, as well as to perform dynamic strain measurements combining the information provided by slope-assisted Brillouin scattering measurements, with those provided by amplitude-based ϕ-OTDR measurements.

Hybrid Distributed Optical Fiber Sensor for the Multi-Parameter Measurements

“…Both Φ-OTDR and COTDR take advantage of the Rayleigh scattering, and BOTDR and BOTDA use SpBS or SBS light for temperature and strain measurements. Apart from the multi-parameter measurement (temperature, strain, vibration, and loss) based on the integration of discrete sensing characteristics [ 145 , 192 , 193 , 194 , 195 , 196 ], there is also a focus on the handling of the temperature/strain cross-sensitivity among the Brillouin scattering-based sensors with the assistance of Rayleigh scattering [ 172 , 197 , 198 ]. In addition, the combination of BOTDA/BOTDR and frequency-sweeping Rayleigh scattering-based DOFS can provide comprehensive and accurate strain or temperature measurements [ 199 , 200 , 201 ].…”

Simulation analysis of axial force on optical fibers in unmanned aerial vehicles based on genetic algorithm

“…During the operation of unmanned aerial vehicles, they are affected by various special flight environments and require the use of a large number of sensors for real-time measurement of their flight parameters. Fiber optic sensors, due to their advantages such as light weight, small size, high temperature resistance, corrosion resistance, and electromagnetic interference resistance, can largely overcome the influence of environmental factors, accurately monitor various parameters of aircraft, timely judge and prevent accidents, and are suitable for parameter monitoring of unmanned aerial vehicles [2].…”

Optimizing multi-parameter distributed fiber sensors: a hybrid Rayleigh-Brillouin-Raman System approach

“…The utilization of multiple scatterings presents a direct approach to building DOFS capable of simultaneously measuring multiple measurands. This has prompted researchers to propose diverse hybrid systems 8 , 9 . One such example involves combining RBS and BS as the foundation for a hybrid system aiming to detect vibration concurrently with strain or temperature.…”

“…One such example involves combining RBS and BS as the foundation for a hybrid system aiming to detect vibration concurrently with strain or temperature. In these systems, Brillouin optical time domain analysis (BOTDA) or reflectometry (BOTDR) is employed to measure strain or temperature, while phase-sensitive optical time domain reflectometry (phase-OTDR or ϕ -OTDR) is utilized for vibration measurement 8 . However, a significant challenge hindering the practical application of this hybrid system is the cross-sensitivity of strain and temperature observed in both RBS and BS signals.…”

“…This approach effectively merges the RBS and BS measurements, ensuring a substantial signal amplitude through SBS while maintaining a single-end access configuration to the sensing fiber. Furthermore, this method simplifies signal processing in contrast to earlier hybrid RBS and BS systems 8 , 9 , as it solely employs the RBS light wave for demodulating the probe for both BS and RBS.…”