A dual-cavity interrogation method used to enhance the unambiguous measurement range of in-fiber Bragg grating sensors with high-resolution interferometric wavelength-shift detection is described. This novel technique is based on the use of two sets of fringes obtained with a stepped interferometric wavelength scanner with dual cavity lengths. We demonstrate the concept by interrogating an in-fiber grating temperature sensor with a stepped Michelson wavelength scanner.
© 1996 Optical Society of America
Y. J. Rao, D. A. Jackson, L. Zhang, and I. Bennion, "Dual-cavity interferometric wavelength-shift detection for in-fiber Bragg grating sensors," Opt. Lett. 21, 1556-1558 (1996)