Research and analysis of Brillouin distributed sensing system based on quasi-single-mode few-mode fiber

Abstract:

A distributed fiber sensor was fabricated by splicing two single-mode fibers (SMFs) using the few-mode fiber (FMF) technique. A Brillouin optical time domain analysis (BOTDA) system was developed to measure the sensor's temperature and bending performance. Two-mode and four-mode step FMFs were combined to splice the few-mode segment. The results indicate that the temperature response coefficients of the few-mode segment are only slightly higher than those of the connected single-mode segment, measuring at 1.13 MHz/°C and 1.12 MHz/°C, respectively. The minimum bending radius for the sensor is 0.9 cm, and the four-mode bending response curve is superior to that of the two-mode one, proving that 4-SI-FMF offers better bending sensitivity.