Research Of Integrated Interferometer Based On Twin-Core Fiber

In this paper, we researched the integrated interferometer based twin-core fiber and itsapplication. The theoretical model of twin-core fiber which has universal applicativesignificance was set up according to coupled mode theory. The transmission character oftwin-core fiber was analysed in detail. Besides, the transmission constant of twin-core fiberand the transverse coupling constant between two cores were calculated. Using two differentkinds of twin-core fiber made by our own laboratory, we fabricated integrated fiber Michelsoninterferometer and fiber Mach-Zehnder interferometer with the tapering technology of simplemode fiber and twin-core fiber. The theoretical analysis of these two interferometers was alsogiven.We studied the application of these two integrated interferometers in sensing andcommunication respectively. Firstly, the application in sensing of Michelson interferometerbased on asymmetrical twin-core fiber was proposed. Because of the effective refractive indexof two cores in twin-core fiber has different response to external environment, the integratedMichelson interferometer was used for measuring refractive index of liquid, the academicsimulation and experiment of this refractometer was researched. Secondly, the application incommunication of Mach-Zehnder interferometer based on symmetrical twin-core fiber wasstudied. We obtained an integrated tunable filter by cascading two Mach-Zehnderinterferometers. According to interference theory, we analysed the transmission character ofsingle Mach-Zehnder interferometer and cascaded Mach-Zehnder interferometers. In addition,the transmission spectrum of this filter was simulated and the filter characteristics wasanalysed. By changing the optical path length difference of two interferometers respectively,we got a widely continuous wavelength-tunable filter finally.