Temperature and strain discrimination of a dual coated superimposed Fiber Bragg Gratings at cryogenic temperatures

摘要

In this work the thermal and strain performance of a dual coated superimposed FBG sensor has been presented. A superimposed gratings with two different wavelengths of 1550 nm and 850 nm has been inscribed at a same location to sense the wavelength shift due to both temperature and strain perturbations. A matrix method is employed to the mixed output sensor signals to discriminate the effects due to strain and temperature. In this paper, the sensor design procedure and the coating thickness determination have been studied in detail. Initial experiments, which demonstrate the sensor operating characteristics at cryogenic temperature has been reported.