L-Band Distributed Raman Amplification Using a Bi-Directional C-Band Erbium Doped Fiber Laser Pumping Scheme

"Operation in the L-band may be useful for broadband DWDM transmission but is limited by the higher fiber attenuation in that region, regardless the fiber type. We present the on-off gain characterization of an L-band Raman amplifier, bi-directionally pumped by two C-band tunable fiber ring lasers and measured with different types of transmission fiber. The main focus of our studies has been on standard and dispersion shifted fibers, aiming L-band system upgrade of already installed fiber plants. The results indicate that L-band distributed Raman amplification allows for the desired bandwidth capacity increase."