Mingjia Shangguan
University of Science and Technology of China, China
Title: Upconversion Brillouin optical-time domain reflectometry
Biography
Biography: Mingjia Shangguan
Abstract
A direct-detection Brillouin optical time-domain reflectometry (BOTDR) using a photon-counting up-conversion detector (UCD) and an all-fiber structure Fabry–Perot scanning interferometer (FFP-SI) is demonstrated with shot-noise limited performance. In order to detect the weak spontaneous Brillouin backscatter signal efficiently, an ultra-low noise equivalent power of the photon-counting UPD is adopted, which up-converts the backscattering signal at 1548.1 nm to 863 nm, and then detected by a Si-APD. The final system efficiency of the UPD is 15% with a noise of 40 counts per second. By using high spectral resolution of the FFP-SI, the Brillouin spectra along a polarization maintain fiber (PMF) is analyzed in the optical frequency domain directly. In comparison with heterodyne BOTDR, direct-detection BOTDR has better EM compatibility and faster speed in data processing. In experiments, with peak input power of 20 dBm, temperature profile along a 9 km PMF is retrieved according to the Brillouin shift, with spatial/temporal resolution of 2 m/15 s. The precision is 0.7ºC at the leading end and 1.2ºC at the trailing end.