Signal conditioning for compensating nonlinearity and nonrepeatability of an optical frequency scanning laser implemented in a C-OFDR system.

Abstract

Reported systems using coherent optical frequency-domain reflectometry, C-OFDR, rely on the linearity of the scanning rate of the tunable laser and sometimes on its repeatability. In this work, we present the implementation of signal-conditioning algorithms for a fiber temperature sensor system based on coherent optical frequency-domain reflectometry. Postacquisition signal conditioning removes any nonlinearity and nonrepeatability effects and allows synchronization of the whole system. A low reflectivity, 0.1%, fiber Bragg grating, placed in a reference interferometer, is implemented for removing the nonrepeatability of the optical source. The spatial resolution achieved by the temperature fiber sensor is 0.36 mm, with repeatability of 0.032°C, while using telecommunication-grade components.