Mode-Dependent Crosstalk Penalty in Few-Mode Multi-Core Fiber Transmission

Space-division multiplexing (SDM) in few-mode multi-core fibers (FM-MCF) allows the transmission of multi-petabit/s data-rates over a single optical fiber. Recently, transmission of more than 1.2 Pbit/s was demonstrated in a FM-MCF with a cladding diameter of 160 μm, compatible with the standard coating diameter of 250 μm [1]. When increasing the core density in FM-MCF or the transmission distance, inter-core crosstalk can limit the achievable data rates. Inter-core crosstalk is strongly wavelength-dependent and higher-order modes in FM-MCF are expected to show a larger crosstalk penalty compared to the fundamental mode, as their mode fields extend farther into the cladding [2]. In this paper, we present an experimental investigation of the crosstalk-induced Q-factor degradation of 16-Quadrature amplitude modulation (16-QAM) signals, transmitted over a four-core three-mode fiber.