Recent Advances in Brillouin Optical Time Domain Reflectometry

Abstract

In the past two decades Brillouin-based sensors have emerged as a newly-developed optical fiber sensing technology for distributed temperature and strain measurements. Among these, the Brillouin optical time domain reflectometer (BOTDR) has attracted more and more research attention, because of its exclusive advantages, including single-end access, simple system architecture, easy implementation and widespread field applications. It is realized mainly by injecting optical pulses into the fiber and detecting the Brillouin frequency shift (BFS), which is linearly related to the change of ambient temperature and axial strain of the sensing fiber. In this paper, the authors provide a review of new progress on performance improvement and applications of BOTDR in the last decade. Firstly, the recent advances in improving the performance of BOTDRs are summarized, such as spatial resolution, signal-to-noise ratio and measurement accuracy, measurement speed, cross sensitivity and other properties. Moreover, novel-type optical fibers bring new characteristics to optic fiber sensors, hence we introduce the different Brillouin sensing features of special fibers, mainly covering the plastic optical fiber, photonic crystal fiber, few-mode fiber and other special fibers. Additionally, we present a brief overview of BOTDR application scenarios in many industrial fields and intelligent perception, including structural health monitoring of large-range infrastructure, geological disaster prewarning and other applications. To conclude, we discuss several challenges and prospects in the future development of BOTDRs.

Experiment Study on Coal Roadways Roof Monitoring Based on the Pre-stretched Optical Fiber Lay out at Fixed-points

“…The basic configuration of BOTDR is shown in figure 1. In the measuring of BOTDR [17], the relationship between the frequency shift and the longitudinal strain and temperature changes in the core / cladding can be approximately expressed by a linear function, as shown in formula (1):…”

Global Temperature Sensing for an Operating Power Transformer Based on Raman Scattering

“…The distributed fiber optic sensing technology, developing rapidly in recent years, has gradually been applied in some super projects such as bridge and tunnel monitoring, petroleum and gas lines monitoring, power transmission lines monitoring, civil engineering, coal mining and so forth. The spatiotemporally continuous detecting advantages furtherly enlarge its application [ 18 , 19 , 20 ].…”

Research on Structure Optimization and Measurement Method of a Large-Range Deep Displacement 3D Measuring Sensor

“…Firstly, due to the strain conduction process between the fiber sensor and the measured object, the measurement accuracy of the sensor is seriously affected. Secondly, the measurement range of the BOTDR technology is small, and the fiber breaks when a large deformation occurs [24,25].Borehole extensometers and settlement meters are often used for longitudinal displacement measurement of rock and soil mass. It is suitable for the initial stage of geotechnical deformation, which is characterized by small deformation and slow change rate [26][27][28].…”

“…Firstly, due to the strain conduction process between the fiber sensor and the measured object, the measurement accuracy of the sensor is seriously affected. Secondly, the measurement range of the BOTDR technology is small, and the fiber breaks when a large deformation occurs [24,25].…”