Employing a single DPLL for joint carrier phase estimation in few-mode fiber transmission

To reduce DSP complexity, both a master/slave and phase-averaged single digital PLL are investigated for a 3×112Gbit/s DP-QPSK transmission over 70km FMF with inline MM-EDFA. A 0.5dB OSNR gain at 3.8×10
^-3
FEC-limit is experimentally demonstrated.