Polarization-Maintaining Multi-Core Few-Mode Fiber With a Cladding Diameter of 125 μm

Abstract

We present the theoretical study of polarization-maintaining multi-core few-mode fiber (PM MC-FMF) with a cladding diameter of 125 μm, in order to secure the maximum number of independent spatial channels arising in the single fiber. By taking both the intercore crosstalk (XT) and the intra-core mode coupling into account, we identify that the PM five-core three-mode fiber is able to provide 19 parallel channels without the need of MIMO signal processing. After the numerical optimizations, the inter-core XT of MC-FMF is less than -30 dB/100km, due to the use of trench-assisted heterogeneous core distribution. Meanwhile, the effective refractive index (RI) differences among both spatial modes and polarization modes are more than 8×10 -4 and 3.26×10 -4 over the C+L band, respectively, due to the introduction of stress and geometric birefringence. Moreover, the cladding diameter of such MC-FMF is the same as that of the standard single-mode fiber (SSMF), leading to a convenient upgrading from the SSMF to the MC-FMF.