High Power, Tunable, Continuous-Wave Fiber Lasers in the L-Band Using Cascaded Raman Amplifiers

We demonstrate a high power, all-fiber, and tunable laser source that can operate in the L-band region. A low power, tunable input laser is amplified with a recently proposed, high efficiency, sixth-order cascaded Raman amplifier. The proposed system is scalable and overcomes the limitations of Erbium and Erbium-Ytterbium co-doped fiber lasers for power scaling. A tunable Erbium-Ytterbium co-doped fiber ring laser generating similar to 0.5 W of power and tunable in 1560-1590 nm wavelength range is utilized as the seed source. The output from the seed laser is amplified to similar to 24 W using sixth-order cascaded Raman amplification. A high power Yb laser operating at 1117 nm is used as the pump laser for driving the Raman conversions. The operating wavelength of the demonstrated laser in the eye-safe, atmospherically transparent region enables high power free-space applications. In addition, this source enables other interesting applications, such as high power supercontinuum generation with conventional silica fibers.