Refractive index sensing of twin-core fiber based on Mach Zehnder interference and SPR effect

Abstract The sensing characteristics of twin-core fiber for refractive index (RI) detection are presented and experimentally investigated. In this work, for the first time, we demonstrate the manufacturing method of optical fiber sensor based on Mach Zehnder interference and surface plasmon resonance. Mode interference and resonance coupling effect are thoroughly realized with the misalignment fusion and silver mirror reaction. It is found that the sensitivity of the proposed sensor is 3020 nm RIU −1 in the RI ranging from 1.3333 to 1.3804, which is much higher than that of the conventional fiber sensor. Moreover, experimental data indicate that this sensor has the advantages of easy fabrication, good repeatability and good stability. According to these characteristics, we introduce one specific application of pregnancy detection to validate the application of the designed sensor in biomedical field.