Refractive Index Sensor based on Hetero-core fiber Interrogated by a Laser/photodetector at 1550 nm

We present an investigation of a hetero-core fiber optic refractive index sensor that performs measurements under the 1550 nm wavelength for chemical and biological applications. The structure is formed by a no-core fiber (N CF) spliced to a multimode optical fiber at each of its ends, forming a Multimode / No-core fiber / Multimode (MNM) structure, where the NCF fiber is the sensing part of the structure. The simple and low-cost interrogation scheme uses a laser and a photodetector. The sensor is able to measure refractive index variations with a resolution of
$9.93\times 10^{-5}$
RIU.