Analysis of high-power double-clad fiber lasers side-pumped by multiple diode-lasers in V-groove configuration

We propose a new method to construct high-power single-mode fiber lasers by multiple diode-lasers side-pumping in V-groove configuration. V-groove side-pumping was first proposed to leave the fiber ends free for splicing to other fibers and realizing mode-lock in the laser cavity. We think it suitable for developing high-power fiber lasers. Compared with end-pumping, this arrangement has at least two advantages. First, it did not require a large G to increase the effective absorption length and the pump efficiency can be kept at high level. Second, it did not require a high-power diode laser to pump at the end of the fiber, and the high-intensity pumping light in the fiber can be easily achieved by multiple diode lasers with medium-power. Using the equations governing the evolution of laser light in the fiber core, we calculated the output power of a 500m-long fiber laser. With ten 40-W diode-laser side-pumping, we can obtain 240 W output power from the double-clad fiber laser and the slope efficiency can reach 68.1%. Such a result implies that more than hundreds to kilowatt output power could be easily achieved with long double-clad fiber and more diode lasers.