title: Hybrid distributed Raman amplification combining random fiber laser based 2nd-order and low-noise LD based 1st-order pumping.
abstract: A configuration of hybrid distributed Raman amplification (H-DRA), that is formed by incorporating a random fiber laser (RFL) based 2nd-order pump and a low-noise laser-diode (LD) based 1st-order pump, is proposed in this paper. In comparison to conventional bi-directional 1st-order DRA, the effective noise figure (ENF) is found to be lower by amount of 0 to 4 dB due to the RFL-based 2nd-order pump, depending on the on-off gain, while the low-noise 1st-order Raman pump is used for compensating the worsened signal-to-noise ratio (SNR) in the vicinity towards the far end of the fiber and avoiding the potential nonlinear impact induced by excess injection of pump power and suppressing the pump-signal relative intensity noise (RIN) transfer. As a result, the gain distribution can be optimized along ultra-long fiber link, due to combination of the 2nd-order RFL and low-noise 1st-order pumping, making the transmission distance be extended significantly. We utilized such a configuration to achieve ultra-long-distance distributed sensing based on Brillouin optical time-domain analysis (BOTDA). A repeater-less sensing distance record of up to 154.4 km with 5 m spatial resolution and ~ ± 1.4 °C temperature uncertainty is successfully demonstrated.
authors.forename: Xin-Hong
authors.initials: XH
authors.lastname: Jia
authors.forename: Yun-Jiang
authors.initials: YJ
authors.lastname: Rao
authors.forename: Cheng-Xu
authors.initials: CX
authors.lastname: Yuan
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Yan
authors.forename: Zi-Nan
authors.initials: ZN
authors.lastname: Wang
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Zhang
authors.forename: Han
authors.initials: H
authors.lastname: Wu
authors.forename: Ye-Yu
authors.initials: YY
authors.lastname: Zhu
authors.forename: Fei
authors.initials: F
authors.lastname: Peng