Scanning-Free High-Resolution Brillouin Optical Correlation Domain Analysis

Brillouin optical correlation-domain analysis (B-OCDA) is a protocol for random-access, distributed and dynamic monitoring of strain and temperature along optical fibers with cm-scale spatial resolution. Current B-OCDA schemes identify the resonance of Brillouin scattering in the fiber through scanning over multiple frequencies in each measurement point. Alternatively, in my work the local Brillouin frequencies are extracted from temporal transient analysis of one of the optical waves. Measurements are taken at only two arbitrary frequencies and no spectral scanning is necessary. The Brillouin frequency of a 2 meters-long fiber was measured with 1 MHz accuracy and a dynamic range of 200 MHz. Transient measurements were also performed in a B-OCDA experiment with 4 cm resolution, experimental uncertainty of ±2.4 MHz and 100 MHz dynamic range. A 4 cm-wide hot-spot was properly identified. Multiple correlation peaks could be addressed in a single trace. Lastly, I present a B-OCDA  protocol with a high spatial resolution of 2 mm, based on amplified spontaneous emission of an erbium-doped fiber amplifier.

* Ph.D. research carried out with the supervision of Prof. Avi Zadok, Faculty of Engineering, Bar-Ilan University.