Low crosstalk 125 μm cladding heterogeneous six-core few-mode fiber with air-hole array and trench structure.

• A novel air-hole array and trench (HAT) structure is proposed. • The 6-core 2-LP fiber with a 125 μm cladding, which is compatible with the current optical fiber communication network. • This fiber exhibits an ICXT is below −38.23 dB/100 km, which is sufficiently low to neglect IMXT. • Compared to SMF, the communication capacity of this fiber has increased by 18 times. In order to be compatible with the current optical fiber communication network, we propose a 125 μm diameter heterogeneous six-core two linear polarization modes fiber with air-hole array and trench (HAT) structure. The coupled power theory and finite element method (FEM) are used to investigate inter-core crosstalk (ICXT), bending loss, and other properties. The HAT structure can effectively suppress ICXT; and the maximum ICXT is less than −38 dB/100 km in C + L band. The effective refractive index difference (Δ n eff) between modes is greater than 3 × 10-3, inter-mode crosstalk (IMXT) can be ignored. The maximum intrinsic loss is 0.187 dB/km; relative core multiplicity factor reaches 32.21. The relative spatial efficiency is 18 times that of traditional single-mode fibers. This fiber can be produced by chemical vapor deposition and existing optical fiber manufacturing technology. The designed fiber can be directly connected to the communication network to reduce the cost of equipment renewal, and the communication capacity can be increased by 18 times. [ABSTRACT FROM AUTHOR]