Abstract
We demonstrate that a distributed Raman amplification scheme based on random distributed feedback (DFB) fiber laser enables bidirectional second-order Raman pumping without increasing relative intensity noise (RIN) of the signal. This extends the reach of 10 × 116 Gb/s DP-QPSK WDM transmission up to 7915 km, compared with conventional Raman amplification schemes. Moreover, this scheme gives the longest maximum transmission distance among all the Raman amplification schemes presented in this paper, whilst maintaining relatively uniform and symmetric signal power distribution, and is also adjustable in order to be highly compatible with different nonlinearity compensation techniques, including mid-link optical phase conjugation (OPC) and nonlinear Fourier transform (NFT).
Highlights
It is well known that distributed Raman amplification improves the transmission performance, compared with lumped amplification such as EDFA
We demonstrate that a distributed Raman amplification scheme based on random distributed feedback (DFB) fiber laser enables bidirectional second-order Raman pumping without increasing relative intensity noise (RIN) of the signal
This extends the reach of 10×116 Gb/s DP-QPSK WDM transmission up to 7915 km, compared with conventional Raman amplification schemes
Summary
It is well known that distributed Raman amplification improves the transmission performance, compared with lumped amplification such as EDFA. We have previously reported an ultra-long Raman fiber laser (URFL) based amplification technique with second-order pump and two fiber Bragg gratings (FBGs) [1]. This technique can give an almost negligible (+/- 0.8 dB) signal power variation (SPV) over an 80 km span. Using backward pumping only is more beneficial but at the expense of an increase in SPV and noise Another interesting feature of using backward pumping only is that a random Rayleigh backscattering distributed feedback (DFB) fiber laser can be generated even in a closed cavity, as opposed to the usual Fabry-Perot lasing obtained when using bidirectional pumping [6]. The first work on random DFB fiber laser based amplification was demonstrated in [8] where the authors showed a transmission performance improvement using third-order backward pumping. Bidirectional pumping using similar scheme can be used in unrepeatered transmission in which the RIN-induced penalty on the signal is significantly low [7,9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
