Parameter analysis of a pair of Bragg gratings with overlapping spectra for power measurement of small deformations

Abstract

Bragg gratings belong to a group of single-point fibre optic sensors that can be simply multiplexed to achieve quasi distributed sensing. As for single-point measurement, conversion of a spectral shift to a reflected power change allows replacing a complexand costly evaluation unitwith a low-cost optical performance monitoring system. This article deals with the design of parameters of a pair of Bragg gratings with overlapping reflection spectra for transforming a spectral shift into a power change. The parameter analysis of Bragg gratings was performed in the OptiSystem SW environment to achieve a large measurement range with a linear response to the measurand. The measurement concept designed is immune to temperature changes. The functionality of the concept was experimentallyverified during the measurement of deformation.