[16p-C32-1~9] 3.8 Optical measurement, instrumentation, and sensor

▲ [16p-C32-1] Brillouin Optical Correlation Domain Reflectometry with Pump Light Frequency Sweeping Scheme

〇(DC)YUGUO YAO¹, MASATO KISHI¹, KAZUO HOTATE¹ (1.The Univ. of Tokyo)

Keywords:optical fiber, Brillouin scattering, optical fiber sensing

Brillouin optical correlation domain reflectometry (BOCDR) is a technique to measure the distributed strain and/or temperature along an optical fiber, by utilizing the dependence of Brillouin frequency shift (BFS) of spontaneous Brillouin scattering on strain and/or temperature. In a standard BOCDR system, the electrical spectrum analyzer (ESA) is used to observe the Brillouin spectrum, by sweeping the frequency of the electrical local oscillator in the ESA. However, in this scheme, the electrical background noise of the ESA may influence the detection of the Brillouin spectrum, especially when the BOCDR system works with a high spatial resolution and the signal is weak and comparable with the intrinsic electrical noise in the ESA. In this paper, we propose the pump light frequency sweeping scheme to overcome this problem. In this scheme, the frequency sweeping is realized in optical domain and the ESA is set under zero-span mode, to eliminate the electrical background noise. The optical frequency sweeping is implemented on the pump light but not the reference light, to avoid the fluctuation of the reference light power.