Fiber Optic Sensors Based on Multicore Structures

Abstract

We present a review of the fundamentals and applications of fiber optic sensors based on multicore coupled structures. The fundamentals of these coupled structures are approached in general for arbitrary distributions of N cores on the foundations of coupled mode theory. The principle of operation of fiber optic sensors using this type of architectures is illustrated via numerical simulations of the simplest coupled structure—the two-core fiber. Illustrative experimental results using fiber optic sensors based on two- and seven-core multicore fibers are shown for a number of applications including temperature, curvature, and refractive index sensing. The main aspects of the performance of multicore fiber sensors are highlighted throughout this chapter and their characteristics, especially their sensitivity, are compared to those of other existing fiber sensing architectures such as fiber Bragg gratings, long period gratings, and photonic crystal fibers, among others.