Journal of Nonlinear Optical Physics & Materials Vol. 23, No. 2 (2014) 1450026 (10 pages) c  World Scientific Publishing Company DOI: 10.1142/S021886351450026X L-band multi-wavelength Brillouin–Raman fiber laser utilizing the reverse-S-shaped section N. A. M. Ahmad Hambali ∗,§ , M. Ali Toor † , Z. Yusoff † and M. Ajiya ‡ ∗ Semiconductor Photonics & Integrated Lightwave Systems (SPILS ), Tun Abdul Razak Laser Laboratory (TAReL), School of Microelectronic Engineering, Universiti Malaysia Perlis, Pauh Putra Main Campus, 02600 Arau, Perlis, Malaysia † Faculty of Engineering, Multimedia University, Cyberjaya 63100, Malaysia ‡ Department of Electrical Engineering, Faculty of Engineering, Bayero University, PMB 3011, Kano, Nigeria § azuramalini@unimap.edu.my Received 24 December 2013 In this paper, we experimentally demonstrated multi-wavelength Brillouin–Raman fiber laser that operates in the L-band wavelength region. The laser structure utilizes the reverse-S-shaped technique. 35 output Brillouin Stokes signals were generated at the injection of 6.3 mW of Brillouin pump power at wavelength of 1580 nm into the laser cav- ity together with a Raman pump power of 891.25 mW. The generated output Brillouin Stokes signals are rigidly separated by 0.08 nm (10 GHz). The structure also provides a high tuning range of 25 nm, from 1570 nm to 1595 nm at the injection of 6.3 mW of Bril- louin pump signal power with a Raman pump signal power of 795.3 mW. The generated Brillouin Stokes signals also have an average peak power of 1.11 mW. Highest optical signal-to-noise ratio of 21 dB was obtained at Brillouin pump wavelength of 1595 nm. Keywords : Nonlinear; stimulated Brillouin scattering; Raman amplification; Brillouin– Raman fiber laser; multi-wavelength. 1. Introduction Stimulated Brillouin scattering (SBS) is one of the most popular nonlinear effects in optical fibers that has been advantageously utilized and extensively studied in recent years. 1,2 SBS manifests through the generation of a backward propagating Stokes signal which appears when the injected input power reaches SBS threshold. The frequency of the Stokes signal is normally downshifted from the frequency of input incident light by a value determined by the material that is used in the fabrication of the fiber. For a silica-based fiber, the value is typically 0.08 nm (10 GHz). 3 SBS has a number of attractive technical characteristics and generated an interest for its exploitation in a number of applications such as optical sensing, 4 optical filtering, 5 narrow-bandwidth amplification 6 and fiber laser. 7 1450026-1