Development of the distributed fiber sensors for applications in civil structures

Prof. Xiaoyi Bao

University of Ottawa

Abstract:

Rayleigh and Brillouin scatterings in fibers result from the interaction of photons with local material characteristic features like density, temperature and strain. By detecting changes in the amplitude, frequency and phase of light scattered along a fiber, one can realize a distributed fiber sensor for measuring localized temperature, strain, vibration and birefringence over lengths ranging from meters to one hundred kilometers. Such a measurement can be made in the time domain or frequency domain to resolve location information in the precision of mm to centimeters. The progress on state of the art technology for sensing performance, in terms of spatial resolution and limitations on sensing length is reviewed. These distributed sensors can be used for disaster prevention in the civil structural monitoring of pipelines, bridges, dams and railroads.

In this talk, I will focus on the design, optimization and limitation of the high precision distributed sensors for static (temperature and strain), and dynamic (vibration and acoustic wave) measurements based on Brillouin and Rayleigh scattering in time and frequency domain, namely, optical time domain reflectrometry (OTDR), and optical frequency domain reflectrometry (OFDR). Finally I will present some of our field test results on static and dynamic measurement, as well as correlation between strain and structural condition.

Biography:

Dr. Xiaoyi Bao is the Canada Research Chair professor (Tier I) in Fiber Optics and Photonics in Physics Department, University of Ottawa. Her research interests range from study nonlinear effects in fibers to make fiber sensors for temperature, strain, vibration, refractive index measurement, random fiber lasers, nano- and micro-fibers for sensors and lasers. Dr. Bao has co-authored over 200 refereed journal publications, 9 book chapters, and four IPs from her group were transferred to industries. She is a fellow of Academy of Science, Royal Society of Canada (RSC), OSA and SPIE. She has recently been honored with the Canadian Association of Physics (CAP) Medal for Outstanding Achievement in Industrial and Applied Physics (2013); Federation of Chinese Canadian Professionals (FCCP) Education Foundation Award of Merit (2012); CAP-INO Medal for Outstanding Achievement in Applied Photonics from the Canadian Association of Physicists (2010).