Enhanced Transmission Performance Using Backward-Propagated Broadband ASE Pump

We propose a novel first order incoherent broadband amplified spontaneous emission (ASE) pump which can be used as a seed pump in dual order backward-pumped distributed Raman amplification. Using this broadband ASE pump mitigates the relative intensity noise (RIN) transfer from the backwardpropagated second order pump to the signal, and extends the reach of 10 × 120 Gb/s DP-QPSK WDM transmission to 7915 km, giving a minimum of 12% (833 km) increase, compared with using low RIN semiconductor laser diode and random distributed feedback fiber laser.