Stepped trenches structure of low crosstalk seven-core five-mode fiber

A novel seven-core five-mode fiber composed of stepped trenches and high index ring is proposed in this paper. Numerical analysis shows that the fiber can stably transmit five LP modes in the C + L band. The effective refractive index difference of the five LP modes at 1.55 μm is more significant than 1.2 × 10-3, which is conducive to the independent transmission of the modes. The inter-core crosstalk of the fiber is less than -160 (dB / km ). Therefore, the fiber can be well used to build a large-capacity optical fiber transmission system.