Quasi-distributed network of low-coherence fiber-optic fabry–pÉrot sensors with cavity length-based addressing

Abstract

Distributed measurement often relies on sensor networks. In this paper, we present the construction of low-coherence fiber-optic Fabry–Pérot sensors connected into a quasi-distributed network. We discuss the mechanism of spectrum modulation in this type of sensor and the constraints of assembly of such sensors in the network. Particular attention was paid to separate the signals from individual sensors which can be achieved by cavity length-based addressing. We designed and built a laboratory model of a temperature sensors network. The employed sensors are low-coherence Fabry–Pérot interferometric sensors in a fiber-optics configuration. The extrinsic sensor cavity utilizes the thermal expansion of ceramics, and the sensors are addressed by the different lengths of the cavities. The obtained test results show that the signal components from each sensor can be successfully separated, and the number of sensors could be expanded depending on the FWHM of the light source.