title: Multi-Stress Monitoring System with Fiber-Optic Mandrels and Fiber Bragg Grating Sensors in a Sagnac Loop.
abstract: Fiber Bragg grating sensors are placed in a fiber-optic Sagnac loop to combine the grating temperature sensors and the fiber-optic mandrel acoustic emission sensors in single optical circuit. A wavelength-scanning fiber-optic laser is used as a common light source for both sensors. A fiber-optic attenuator is placed at a specific position in the Sagnac loop in order to separate buried Bragg wavelengths from the Sagnac interferometer output. The Bragg wavelength shifts are measured with scanning band-pass filter demodulation and the mandrel output is analyzed by applying a fast Fourier transform to the interference signal. This hybrid-scheme could greatly reduce the size and the complexity of optical circuitry and signal processing unit, making it suitable for low cost multi-stress monitoring of large scale power systems.
authors.affiliation: Division of Electronics and Information Engineering, Chonbuk National University, Jeonju 561-756, Korea. dldpavl@jbnu.ac.kr.
authors.forename: Hyunjin
authors.initials: H
authors.lastname: Kim
authors.affiliation: Division of Electronics and Information Engineering, Chonbuk National University, Jeonju 561-756, Korea. sjumesh@jbnu.ac.kr.
authors.forename: Umesh
authors.initials: U
authors.lastname: Sampath
authors.affiliation: Division of Electronics and Information Engineering, Chonbuk National University, Jeonju 561-756, Korea. msong@jbnu.ac.kr.
authors.forename: Minho
authors.initials: M
authors.lastname: Song
keywords: Sagnac interferometer; attenuator; fiber Bragg grating