Mode-multiplexed transmission over a 184-km DGD-compensated few-mode fiber span

We transmitted 5 wavelength channels and 6 spatial-and polarization modes over a 184 km long hybrid span few-mode fiber span. Low-loss 3-spot mode couplers are used in combination with backward pumped distributed Raman amplification. The 40-Gbit/s QPSK signals with an aggregate line-rate of 1.2 Tbit/s were recovered by coherent multiple-input-multiple-output off-line digital signal processing.