Fourier‐transform phase comparator for the measurement of extrinsic Fabry–Perot interferometric sensors

Abstract

Abstract A Fourier‐transform phase comparator is developed to measure fiber optic extrinsic Fabry‐Perot interferometric sensors. The phase comparator is realized by comparing the phases of two white‐light spectra, which are obtained by scanning the wavelength of the light source. The changes of a cavity length, which are concerned in most applications, can be interrogated. A linear output is obtained, and a measurement resolution of 15 pm is experimentally achieved, which is very close to the theoretical value. The technique has high resolution and a large dynamic measurement range. In addition, the measurement is not affected by various imperfections of the sensor, light source spectrum profile, and the loss of leading fiber and connectors. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2621–2625, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23719