High-Speed Quasi-Distributed Optical Fiber Sensing Based on Ultra-Weak Fiber Bragg Gratings

Invention of silica based optical fiber not only led to revolution in communication but also provided fundamental basis for many research areas. One example area is distributed optical fiber sensing, which has been attracting research interests for decades. Optical fiber sensors are immune to electromagnetic interference, and resistant to corrosion and can endure harsh environment so they have found applications such as structural health monitoring, intrusion detection and oil downhole measurement. Significant research efforts have been paid to fiber sensing area, many techniques have been developed and some of them have been successfully demonstrated, however achieving both high-speed and long-range is still under intensive research. This dissertation proposes and demonstrates a technique with the capability of simultaneous long-range and high-speed sensing by employing serial ultra-weak fiber Bragg gratings (UW-FBGs) and dispersive components. Various factors which have influence on the system performance, including wavelength resolution, spatial resolution and sensing rate, are analyzed. Different types of light sources and dispersive units were designed and a sensing system was built. With this system, both static and dynamic response were measured, and a sensing link consisting of more than 2000 UW-FBGs was successfully measured at the speed of 20kHz. The noise sources of the system were also theoretically analyzed and experimentally measured. This demonstrated sensing technique can be applied to long range temperature and strain sensing.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Electrical Engineering

Department dc:contributor.department

Electrical and Computer Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2017

Author dc:creator

• Ma, Lingmei

Chair dc:contributor.committeechair

• Wang, Anbo

Committee members dc:contributor.committeemember

• Beex, Aloysius A.
• Zhu, Yizheng
• Pickrell, Gary R.
• Xu, Yong

• fiber Bragg grating
• ultra-weak
• sensing
• fiber dispersion

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:9554

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/74429