Characterization and application of Brillouin scattering-based distributed fiber optic sensor

Abstract

Brillouin scattering based distributed fiber optic sensing as a novel technique has attracted much attention in both research and application for the past ten years. The fiber optic group at the University of Ottawa has developed an advanced automatic Brillouin sensing system and improved it continuously. This thesis presents the characterization and optimization of this sensing system and a series of successful applications both in the laboratory and in the field. Several parameters have been studied around the pulse generation subsystem: such as, bias, leakage, PW voltage, pulsewidth, and repetition frequency. Bias is found to be the most important parameter. We also discuss the relationships between the system repeatability and control parameters such as bias, polarization states, averages and frequency lock methods. Four successful applications of the distributed Brillouin sensing system are reported in the thesis. They are strain measurement in a reinforced concrete beam, simultaneous strain and temperature monitoring of composite curing process, strain and temperature monitoring of a concrete structure, and temperature compensated strain measurement of the load test on the Rollinsford Bridge.