A calibrated 27-km distributed fiber temperature sensor based on microwave heterodyne detection of spontaneous Brillouin backscattered power

This paper presents new techniques designed to improve the performances of a BOTDR. The first one introduces a second pump to the sensor, thus doubling the Brillouin signal on the receiver. The second one uses image processing with a two-dimensional Gaussian filter whose parameters are defined. The last technique explores the possibilities offered by colour codes. The benefits of each, in terms of signal-to-noise ratio, is presented by comparing measurements over a distance range of 50km with a spatial resolution of 5m. These techniques can easily be combined and the global improvement is estimated at 10dB, compared to conventional sensors.

Section: Dual Pump Configurationmentioning

confidence: 99%

New improvements for Brillouin optical time-domain reflectometry

Floch

Sauser

2017

“…The controller module makes other modules of the OFSI act as a defined program so as to realize the functions that represent the OFSI. In OTDR based optical fiber sensing technologies, the controller module coordinates with the pulse generator module to generate optical pulse, synchronizes the optical pulse sending and scattering data receiving, and the acquired data processing and analyzing, and in BOTDA or COTDR [1][2][3][4][5][6][7][8] …”

Section: Standard Processing Chassismentioning

confidence: 99%

“…The distributed optical fiber sensing technologies have been greatly developed in recent thirty year, and corresponding instruments such as OTDR, BOTDR, COTDR, ROTDR, BOTDA, OFDR [1][2][3][4][5][6][7][8][9][10][11][12], have appeared in engineering application fields. The sensing mechanisms are generally based on light scattering, such as Rayleigh scattering, Brillouin scattering and Raman scattering, and the principles for distributed optical fiber sensing are optical time domain or optical frequency domain technologies.…”

Section: Introductionmentioning

confidence: 99%

Design of distributed optical fiber sensing instrument by functionally divided modules

Liu

Liang

et al. 2015

Distributed optical fiber sensing technologies and corresponding instruments have been greatly developed in the recent 30 years. Many instruments such as optical time domain reflectometry (OTDR), Brillouin optical time domain reflctometry (BOTDR), Brillouin optical time domain analyzer (BOTDA), Raman optical time domain reflectometry (ROTDR), coherent optical time domain reflectometry (COTDR), optical frequency domain reflectometry (OFDR) and so on, have been playing important roles in structure health monitoring and other fields needing distributed status parameter sensing. However, these distributed optical fiber sensing instruments produced by different companies or institutes do not follow the same standards and their structure has huge difference. To build a universal structure standard for the distributed optical fiber sensing instruments (OFSI), a concept which adopts functionally divided modules to define OFSI is proposed and its feasibility is discussed. Generally, OFSI can be divided into five functional modules: controller module, pulse generator module, photo-electric module, signal gathering and processing modules and standard processing chassis module. Then the characteristics of OFSI are embodied mostly by the photo-electric modules. The novel method makes full use of the common functional parts and enhances the flexibility of OFSI, which can reduce the cost of OFSI. Additionally, to produce an instrument by functionally divided modules is a technical trend, and it will promote the standardization of OFSI.

“…They can measure strain or temperature at all points along the sensing fiber and may be tens of kilometers long [3,4]. Much research has been focused on improving the spatial, strain and temperature resolutions of these systems, as well as sensing length, mainly by the use of signal processing and improved instrumentation [5,6].…”

Section: Introductionmentioning

confidence: 99%

Optical fiber characterization for optimization of a Brillouin-scattering-based fiber optic sensor

Brown

Colpitts

2004

Brillouin scattering-based distributed fiber optic sensors have been shown to be effective diagnostic tools for monitoring structural health and detecting fires and hot spots, among other uses. Current research has mainly been focused on improving the spatial, strain and temperature resolutions, and sensing lengths of these systems, generally by the use of better signal processing and improved equipment. In contrast, there has been little published work on optimizing the sensing optical fiber itself. A number of commercially available optical fibers have been measured in order to determine how to optimize their Brillouin characteristics. Some characteristics chosen are the number of Brillouin peaks, the frequency of the peaks, their linewidth, and the temperature and strain coefficients of each peak. It is shown that lowering the intrinsic Brillouin frequency of the fiber can increase the Brillouin strain coefficient and decrease the temperature coefficient of the optical fiber for the main Brillouin peak, among other results.