Design of 125-μm cladding diameter multicore fibers with high core multiplexing factor for wideband optical transmission

We propose improved design of heterogeneous trench-assisted multicore fibers (MCFs) for wideband space division multiplexing (SDM) optical transmission. By adopting different parameters for heterogeneous cores, the trade-off among the effective area (Aeff ), cut-off wavelength (λcc ), and crosstalk (XT) was balanced. Different optimization approaches for long-haul and short-reach transmission applications have been adopted. A 125-μm cladding diameter 6-core fiber with Aeff = 90 μm2 , λcc = 1300 nm and XT < −30 dB/100 km at 1550-nm wavelength was designed for long-haul transmission. The designed MCF has a relative core multiplexing factor (RCMF) of 6.75, which is the highest value among the reported uncoupled MCFs with compatible bandwidth. Another 125-μm cladding diameter 8-core fiber with an Aeff = 80 μm2 , λcc = 1300 nm, and XT < −40 dB/km at 1550-nm wavelength was designed for short-reach application and a RCMF of 8.00 was achieved. The XT in both fibers are bending-insensitive due to the small critical bending radius (Rpk ) of 7 cm for 6-core fiber with an Aeff = 90 μm2 and 5 cm for 8-core fiber with Aeff = 80 μm2 , respectively. The designed fibers are promising for high-density wideband SDM transmission.