Title :
A four-element fiber grating sensor array with phase-sensitive detection
Author :
Weis, R.S. ; Kersey, A.D. ; Berkoff, T.A.
Author_Institution :
Opt. Techniques Branch, Naval Res. Lab., Washington, DC, USA
Abstract :
A four-element, time-division multiplexed, fiber grating sensor array operating between the wavelengths of 1280 and 1310 nm was constructed and tested. The array consists of a 1300-nm edge-emitting LED that illuminates four gratings spaced five meters apart. Each grating in the array reflects a spectrally narrow-band (0.3-0.5 mn) wavelength region. Measurand-induced changes in the grating period change the wavelength of the light reflected by each grating. The wavelength shifts are converted to phase changes by routing the reflected signal through a nearly path balanced fiber Mach Zehnder interferometer. The minimum detectable strain was measured to be as low as 2 nanostrain//spl radic/(Hz) for frequencies greater than 10 Hz.<>
Keywords :
Mach-Zehnder interferometers; diffraction gratings; fibre optic sensors; light emitting diodes; light interferometers; strain measurement; time division multiplexing; 1280 to 1310 nm; edge-emitting LED; four-element fiber grating sensor array; grating period; measurand-induced changes; minimum detectable strain; nearly path balanced fiber Mach Zehnder interferometer; phase changes; phase-sensitive detection; reflected signal; spectrally narrow-band; time-division multiplexed; wavelength region; wavelength shifts; Fiber gratings; Light emitting diodes; Narrowband; Optical fiber sensors; Optical fiber testing; Phased arrays; Sensor arrays; Strain measurement; Wavelength conversion; Wavelength measurement;
Journal_Title :
Photonics Technology Letters, IEEE
