Long distance crosstalk-supported transmission using homogeneous multicore fibers and SDM-MIMO demultiplexing

We propose and evaluate the use of spatial-division multiplexing (SDM) multiple input multiple output (MIMO) systems to support long distance transmission using single-mode homogeneous multicore fibers. We show that on a uniform link with per-span inter-core skew compensation, the required SDM-MIMO memory length corresponds to the largest inter-core skew per span on the link. Furthermore, we show that with inter-core skew compensation, the required memory length of the SDM-MIMO is nearly constant with the transmission distance for accumulated crosstalk below -11 dB. We experimentally demonstrate the use of SDM-MIMO with a memory length of 20 ns on a long distance transmission link using 20 GBaud PDM-QPSK signals. We achieve a reach of 9780 km, which corresponds to a 9% improvement over the case without SDM-MIMO. We also show that the use of SDM-MIMO is applicable to the transmission of signals with higher modulation order, achieving transmission reach improvements of 14% for 20 GBaud PDM-16QAM and PDM-64QAM signals.