Tunable Raman fiber laser induced by Rayleigh back-scattering in an ultra-long cavityA. R. Sarmani, R. Zamiri, M. H. Abu Bakar, B. Z. Azmi, A. W. Zaidan and M. A. MahdiJ. Eur. Opt. Soc.-Rapid Publ., 6 (2011) 11043DOI: https://doi.org/10.2971/jeos.2011.11043