Physics and applications of Raman distributed optical fiber sensing

Abstract

Raman distributed optical fiber sensing has been demonstrated to be a mature and versatile scheme that presents great flexibility and effectivity for the distributed temperature measurement of a wide range of engineering applications over other established techniques. The past decades have witnessed its rapid development and extensive applicability ranging from scientific researches to industrial manufacturing. However, there are four theoretical or technical bottlenecks in traditional Raman distributed optical fiber sensing: (i) The difference in the Raman optical attenuation, a low signal-to-noise ratio (SNR) of the system and the fixed error of the Raman demodulation equation restrict the temperature measurement accuracy of the system. {ii) The sensing distance and spatial resolution cannot be reconciled. (iii) There is a contradiction between the SNR and measurement time of the system. (iv) Raman distributed optical fiber sensing cannot perform dual-parameter detection. Based on the above theoretical and technical bottlenecks, advances in performance enhancements and typical applications of Raman distributed optical fiber sensing are reviewed in this paper. Integration of this optical system technology with knowledge based, that is, demodulation technology etc. can further the performance and accuracy of these systems.

Integrated sensing and communication in an optical fibre

“…Among the numerous optical fibre sensors, distributed optical fibre sensing (DOFS) interrogates a large number of points in a single sensing fibre, thus providing an overwhelming advantage over conventional node-type sensors in longdistance measurement [6][7][8] . In particular, DOFS techniques based on backscattered light (including Rayleigh [9][10][11] , Brillouin 12,13 , and Raman 14 ) take into account both the measurement accuracy and sensing distance, hence attracting much attention and intensive study over the last few decades. For these techniques, not only the intrinsic fibre characteristics (length, attenuation, breakpoints 15 , and optical fibre diameter 16 ) but also a variety of physical parameters (such as temperature 17 , strain 18 , pressure 19 , seismic wave 20,21 , and refractive index 22,23 ) can be measured with high resolution.…”

New concept of permafrost degradation monitoring based on photonics technologies: Case study from Calypsostranda (Bellsund, Svalbard)

“…Most commercially available interrogation devices based on Rayleigh scattering (such as OTDR—optical time‐domain reflectometer and φ‐OTDR—phase‐sensitive OTDR, also known as DAS—distributed acoustic sensor and DVS—distributed vibration sensor), as well as on Raman DTS and Brillouin (BOTDR/BOTDA—Brillouin optical time‐domain reflectometer/analyser also known as DTSS—distributed temperature and strain sensor) have spatial resolution of an order of meters (Fernández‐Ruiz et al, 2022; Li & Zhang, 2022; Lu et al, 2019; Palmieri et al, 2022; Schenato, 2017; Silva et al, 2022); however, a Rayleigh‐scattering‐based optical frequency‐domain reflectometer (OFDR), based on the same measurement technique as certain implementation of light detection and ranging (LiDAR) (Ding et al, 2018), namely frequency‐modulated continuous‐wave (FMCW), has commercially available implementation that allows for a spatial resolution of 1 cm for sensing range of 70 m (Liang et al, 2021).…”

A mode-locked random laser generating transform-limited optical pulses

“…Although one Kelvin temperature sensitivity and metre-long spatial resolution suffice in many cases, such as in oil-well facilities, in other applications, such as monitoring water seepage through temperature variation in dams and dikes to prevent accidents, much better performance parameters are advantageous [37]. Typically, distributed temperature sensors (DTS) make use of the relative intensities of Stokes and anti-Stokes signals from Raman scattering in fibres, monitored via optical time domain reflectometry [38,39]. Wavelength-dependent loss due to fibre bending or ageing is a problem that single-wavelength monitoring systems do not have.…”