Recent Advances in Forward Brillouin Scattering: Sensor Applications

Abstract

In-fiber opto-mechanics based on forward Brillouin scattering has received increasing attention because it enables sensing the surrounding of the optical fiber. Optical fiber transverse acoustic resonances are sensitive to both the inner properties of the optical fiber and the external medium. A particularly efficient pump and probe technique—assisted by a fiber grating—can be exploited for the development of point sensors of only a few centimeters in length. When measuring the acoustic resonances, this technique provides the narrowest reported linewidths and a signal-to-noise ratio better than 40 dB. The longitudinal and transverse acoustic velocities—normalized with the fiber radius—can be determined with a relative error lower than 10−4, exploiting the derivation of accurate asymptotic expressions for the resonant frequencies. Using this technique, the Poisson’s ratio of an optical fiber and its temperature dependence have been measured, reducing the relative error by a factor of 100 with respect to previously reported values. Using a single-point sensor, discriminative measurements of strain and temperature can be performed, achieving detection limits of ±25 με and ±0.2 °C. These results show the potential of this approach for the development of point sensors, which can be easily wavelength-multiplexed.

Brillouin interaction between single optical modes excited in multimode fibers

“…9). In addition, the forward Brillouin scattering in optical fibers [58][59][60][61][62][63] could be of particular interest for further studies due to its practical importance for soliton fiber lasers as an effect enabling the stabilization of harmonically mode-locked laser operation and super-mode noise reduction 64-69 .…”

Brillouin-like effects in rare-earth-doped bi-directional optical fiber amplifiers

“…In light of these effects, the Brillouin-like amplification could enrich the advanced Brillouin applications such as slow light [41][42][43][44] , stored light [45][46][47][48] , narrowband RF photonic filters [49][50][51] , optical processing [52][53][54] , distributed sensing [55][56][57][58][59][60] , narrowband spectrometers 61,62 , optical amplifiers 63 , narrow linewidth, spectrally pure RF sources 64,65 among others. The PIDG analog of the forward Brillouin scattering in optical fibers [66][67][68][69][70][71] could be of particular interest for further studies due to its enormous potential for practical applications in soliton fiber lasers as the method enabling the stabilization of harmonically mode-locked laser operation and super-mode noise reduction [72][73][74][75][76][77] . New mechanisms are important as well for designers of the Brillouin and random fiber lasers [78][79][80][81][82][83][84]…”

Fiber-Optic System for Monitoring Pit Collapse Prevention

“…Moreover, FOS are widely used [8]. The reasons for the development were the decrease of the materials cost and improvements in measurement tools [9]. The main methods of measuring external impacts include Tunable Wavelength Coherent Optical Time Domain Reflectometry (TW-COTDR), Phase Shift Pulse Brillouin Optical Time Domain Reflectometry (PSP-BOTDR), Pulse-Prepump Brillouin Optical Time Domain Analysis (PPP-BOTDA), Brillouin Optical Time Domain Analysis (BOTDA), Brillouin Optical Time Domain Reflectometry (BOTDR), Optical Frequency Domain Reflectometry (OFDR) or methods based on measuring losses in an OF caused by Brillouin scattering [10].…”