Title :
Fiber Bragg grating interrogation and multiplexing with a 3/spl times/3 coupler and a scanning filter
Author :
Johnson, Gregg A. ; Todd, Michael D. ; Althouse, Bryan L. ; Chang, C.C.
Author_Institution :
Sect. of Fiber Opt. Smart Structures, U.S. Naval Res. Lab., Washington, DC, USA
Abstract :
We present a new technique for fiber Bragg grating (FBG) sensor interrogation and multiplexing. The technique combines a scanning bandpass filter used to multiplex by wavelength multiple gratings in a single fiber, and an unbalanced Mach-Zehnder fiber interferometer made with a 3/spl times/3 coupler to detect strain-induced wavelength shifts. A demonstration system interrogates four gratings in a single fiber at a sampling rate up to 20 kHz, with a noise floor measured at less than 10 n/spl epsiv///spl radic/(Hz) above 0.1 Hz.
Keywords :
Bragg gratings; Mach-Zehnder interferometers; fibre optic sensors; multiplexing; optical fibre couplers; optical fibre filters; optical scanners; 3/spl times/3 coupler; fiber Bragg grating interrogation; fiber Bragg grating sensor interrogation; multiplexing; noise floor; scanning bandpass filter; scanning filter; single fiber; strain-induced wavelength shifts; unbalanced Mach-Zehnder fiber interferometer; wavelength multiple gratings; Band pass filters; Bandwidth; Bragg gratings; Fiber gratings; Noise measurement; Optical fiber couplers; Optical fiber sensors; Voltage control; Wavelength division multiplexing; Wavelength measurement;
Journal_Title :
Lightwave Technology, Journal of
