[1] Zhu B, Borel P, Carlson K et al[J]. Unrepeatered transmission of 3.2 Tb/s (32×120 Gb/s) over 445 km fiber link IEEE Photonics Technology Letters, 25, 1863-1866.

[2] Gainov V, Gurkin N, Lukinih S et al. Record 500 km unrepeatered 1 Tbit/s (10×100 G) transmission over an ultra-low loss fiber[J]. Optics Express, 22, 22308-22313(2014). http://www.opticsinfobase.org/abstract.cfm?URI=oe-22-19-22308

[3] [3] BissessurH, EtienneS, BousseletP, et al.6 Tb/s unrepeatered transmission of 60×100 Gb/s PDM-RZ-QPSK channels with 40 GHz spacing over 437 km[C]∥European Conference and Exhibition on Optical Communications, September 16-20, Amsterdam, Netherlands. Washington: OSA Publishing. 2012: Mo.1.C.3.

[4] Chi R H, Li L E, Li X Q et al. Stimulated Brillouin Scattering suppressed EDFA in a long-haul optical fiber link system. [C]∥2015 14th International Conference on Optical Communications and Networks, July 3-5, Nanjing, China. New York: IEEE, 150-152(2015).

[5] Feng Y, Jiang H W, Zhang L. Advances in high power Raman fiber laser technology[J]. Chinese Journal of Lasers, 44, 0201005(2017).

[6] Zhu B Y, Borel P, Carlson K et al. Unrepeatered transmission of 6.3 Tb/s (63×128 Gb/s) over 402-km fiber link[J]. IEEE Photonics Technology Letters, 26, 1711-1714(2014). http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6844859

[7] Chen J, Zhou Q X, Lin Y T et al. Optimization design of multi-pump Raman fiber amplifiers based on artificial bee colony algorithm[J]. Acta Optica Sinica, 38, 0606002(2018).

[8] Long Q Y, Wu T W, Hu S M et al. Threshold characteristics of forward-pumped fiber Raman amplifier[J]. Laser & Optoelectronics Progress, 51, 030603(2014).

[9] Zhang F, Zhang W, Feng X et al. Remotely pumped erbium doped fiber amplifiers using low power pump in ultra-long span dense wavelength division multiplexing systems[J]. Acta Photonica Sinica, 35, 1358-1362(2006).

[10] Zhu Y. Fludger C R S, Lee W S, et al. Experimental comparison of all-Raman vs. Raman/EDFA hybrid amplification with 40 Gb/s-based ETDM/DWDM transmissions over 400 km TW-RS fibre. [C]∥Optical Fiber Communication Conference and Exhibit, March 17-22, Anaheim, CA, USA. New York: IEEE, 552-554(2002).

[11] Do-il C, Wayne P, Pallavi P et al. . 8×120 Gb/s unrepeatered transmission over 444 km (76.6 dB) using distributed Raman amplification and ROPA without discrete amplification[J]. Optics Express, 19, B971-B977(2011). http://www.ncbi.nlm.nih.gov/pubmed/22274128

[12] Raupach S M F, Koczwara A, Grosche G et al. . Bi-directional optical amplifiers for long-distance fibre links. [C]∥European Frequency and Time Forum & International Frequency Control Symposium, July 21-25, Prague, Czech Republic. New York: IEEE, 883-884(2013).

[13] Yuan W G, Li Y T, Xiang M et al. Research on power OTN ultra-long haul transmission scheme based on bidirectional Raman[J]. Electric Power Information Technology, 14, 108-111(2016).

[14] Bromage J, Bouteiller J C, Thiele H J et al. WDM transmission over multiple long spans with bidirectional Raman pumping[J]. Journal of Lightwave Technology, 22, 225-232(2004). http://ieeexplore.ieee.org/xpls/icp.jsp?arnumber=1266698

[15] Mizuochi T, Kinjo K, Kajiya S et al. Bidirectional unrepeatered 43 Gb/s WDM transmission with C/L band-separated Raman amplification[J]. Journal of Lightwave Technology, 20, 2079-2085(2002). http://www.opticsinfobase.org/abstract.cfm?uri=JLT-20-12-2079

[16] Chi R H, Li X Q, Sun X H. Optimized amplification scheme in unrepeated DWDM system over 325 km G.652 fiber. [C]∥2015 14th International Conference on Optical Communications and Networks, July 3-5, Nanjing, China. New York: IEEE, 1-3(2015).

[17] Agrawal G P[M]. Nonlinear fiber optics(1989).