Characterization of Multimode Interference Based Optical Fiber

Abstract

Abstract In this paper, the fiber optic cascade based on multimode interference (MMI) is demonstrated and investigated via COMSOL Multiphysics software. Two different cascades were adopted in this work, namely, single mode–multimode–single mode (SMS) and single mode–No–Core–single mode fiber (SNS). The transmission spectrum tuning range depending on the geometrical dimensions of the midst fiber (MMF and NCF). According to the results, the achieved tuning range due to the diameter fiber changing is higher than that of the length changing. The high tunability about 171 nm is achieved within the SMS cascade for the diameter changes from 61 µm –to– 64 µm and about 340 nm is achieved within the SMS cascade for the length changes from 3.9 mm –to– 4.9 mm. In addition, the increasing in the midst fiber diameter caused a red shift in the peak wavelength of the transmission spectrum. While, the increasing in the fiber length caused a blue shift in the wavelength. The calculated lengths for the NCF show good agreement with results that achieved from the simulation software with a total deviation about 0.46 %. While its about 6.5 % for the MMF, since the cladding refractive index is not considered in the theoretical model.