Overcoming degradation in spatial multiplexing systems with stochastic nonlinear impairments

Single-mode optical fibres now underpin telecommunication systems and have allowed continuous increases in traffic volume and bandwidth demand whilst simultaneously reducing cost- and energy-per-bit over the last 40 years. However, it is now recognised that such systems are rapidly approaching the limits imposed by the nonlinear Kerr effect. To address this, recent research has been carried out into mitigating Kerr nonlinearities to increase the nonlinear threshold and into spatial multiplexing to offer additional spatial pathways. However, given the complexity associated with nonlinear transmission in spatial multiplexed systems subject to random inter-spatial-path nonlinearities it is widely believed that these technologies are mutually exclusive. By investigating the linear and nonlinear crosstalk in few-mode fibres based optical communications, we numerically demonstrate, for the first time, that even in the presence of significant random mixing of signals, substantial performance benefits are possible. To achieve this, the impact of linear mixing on the Kerr nonlinearities should be taken into account using different compensation strategies for different linear mixing regimes. For the optical communication systems studied, we demonstrate that the performance may be more than doubled with the appropriate selection of compensation method for fibre characteristics which match those presented in the literature

Few mode multicore photonic lantern multiplexer

We demonstrate an all-fiber multi-mode, multi-core photonic lantern mode multiplexer for SDM applications. Selective excitation of 21 spatial channels, LP01 and LP11a,b modes in 7 cores, with insertion losses below 0.4dB is obtained

Few-mode erbium-doped fiber amplifier with photonic lantern for pump spatial mode control

We demonstrate a few-mode erbium-doped fiber amplifier employing a mode-selective photonic lantern for controlling the modal content of the pump light. Amplification of six spatial modes in a 5 m long erbium-doped fiber to x223C;6.2x2009;x2009;dBm average power is obtained while maintaining high modal fidelity. Through mode-selective forward pumping of the two degenerate LP21 modes operating at 976 nm, differential modal gains of lt;1x2009;x2009;dB between all modes and signal gains of x223C;16x2009;x2009;dB at 1550 nm are achieved. In addition, low differential modal gain for near-full C-band operation is demonstrated