Abstract
Although the proof of concept for slope-assisted (SA-) Brillouin optical correlation-domain reflectometry (BOCDR) has been demonstrated, no reports on its detailed operation have been provided to date. We theoretically and experimentally investigate the relationship between the system output (power-change distribution) of SA-BOCDR and the actual Brillouin frequency shift (BFS) distribution along the sensing fiber and show that these two are not identical. When the strained fiber section is much longer than the nominal spatial resolution, the actual distribution of the BFS (i.e., strain) is well reproduced by the power-change distribution. However, when the length of the strained section is equal to or only a few times the nominal resolution, the correct BFS distribution cannot be directly obtained. Even when the strained section is shorter than the nominal resolution, a shift in the power change can still be observed, which is not the case for standard BOCDR systems. This unique "beyond-nominal-resolution" effect will be of great use in practical applications.
Highlights
Due to increasing demand for structural health monitoring of civil infrastructure, a variety of fiber-optic sensors have been extensively studied [1,2,3]
We have recently developed another high-speed configuration, motivated by previous implementations in the time domain [31,32,33], called slope-assisted (SA-) Brillouin optical correlation-domain reflectometry (BOCDR) [34], in which the spectral power of the Brillouin gain spectrum (BGS) is exploited to deduce the Brillouin frequency shift (BFS)
When the strained section was sufficiently longer than the nominal spatial resolution, the system output almost corresponded to the actual BFS distribution
Summary
Due to increasing demand for structural health monitoring of civil infrastructure, a variety of fiber-optic sensors have been extensively studied [1,2,3]. We have recently developed another high-speed configuration, motivated by previous implementations in the time domain [31,32,33], called slope-assisted (SA-) BOCDR [34], in which the spectral power of the Brillouin gain spectrum (BGS) is exploited to deduce the Brillouin frequency shift (BFS). This configuration can potentially allow for higher-speed operation than the phase-detection-based method, and for detection of changes in strain and temperature, and optical losses, if necessary. In standard BOCDR systems based on frequency information, these two distributions have been proven to be identical, in principle; in an SA-BOCDR system based on power information, no report has been made so far
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
