Pilot demonstration of correlation-domain distributed temperature sensing using forward Brillouin scattering

Abstract

Forward Brillouin scattering (FBS) has been regarded as a key tool for distributed sensing of strain, temperature, acoustic impedance, etc. To date, FBS-based distributed sensing has been experimentally reported only by time-domain techniques. In this paper, we demonstrate correlation-domain distributed temperature sensing using cascaded FBS seeded by backward stimulated Brillouin scattering (SBS). By localizing the backward SBS using synthesized optical coherence function, cascaded FBS can also be localized. In the proof-of-concept experiment, we detect a 104-m-long heated section in a 397-m-long highly nonlinear fiber.

Error compensation in Brillouin optical correlation-domain reflectometry by combining bidirectionally measured frequency shift distributions

“…We showed that this configuration can effectively mitigate such systematic errors, except for the cases where the intrinsic BFS is asymmetrically distributed outside the strained section. Compared to the injection-locking technique previously reported for BOCDA [20], our method can be easily implemented and is more compatible with BOCDR than BOCDA. However, we need to admit that this configuration spoils one of the most important merits of BOCDR, i.e., single-end accessibility.…”

“…By sweeping the modulation frequency, the position of the correlation peak can be scanned along the FUT, and the distributed information of the Brillouin gain spectrum (BGS) and/or the Brillouin frequency shift (BFS) can be obtained. In most of the BOCDA and BOCDR systems reported so far [15][16][17][18][19][20][21][22][23] (with a small number of exceptions [24][25][26]), a direct modulation scheme, in which the laser driving current was directly modulated to achieve optical frequency modulation (FM), was employed because of its simplicity and cost efficiency. However, the direct modulation scheme suffers from inevitable amplitude modulation (AM), which sometimes deteriorates the system performance such as spatial resolution [27,28].…”

Liquid Leakage Sensor With a V-Shaped Defect Coupling Structure Based on Polymer Optical Fibers

“…Because of the cross-sensitivity of acoustic signals, these measurement methods are of limited efficacy in complex spaces. Optical fibers can be arranged in complex spatial structures and can resist electromagnetic interference, so their usage has received extensive attention [11][12][13][14].…”

Discriminative sensing of temperature and acoustic impedance by using forward Brillouin scattering in large effective area fiber

“…[1][2][3][4] FBS can also be utilized to achieve fiber optic temperature or strain measurements. [5][6][7][8][9][10] Different from backward stimulated Brillouin scattering (BSBS) caused by longitudinal acoustic modes, FBS is induced by transverse modes, which are radial acoustic modes (R 0,m ) and torsional-radial modes (TR 2,m ). The fact that FBS occurs by the transverse acoustic waves enables the FBS effect to be applied to acoustic impedance sensing.…”

“…In this letter, we present our findings that the frequency shift dependencies of R 0,m induced FBS spectra on acoustic impedance are different with different R 0,m modes in large effective area fiber (LEAF), which are similar to their frequency shift dependencies on temperature. 5,6,8,10) Then using two R 0,m modes that would achieve the minimum measurement error, we implement discriminative measurement of temperature and acoustic impedance.…”