Search

We report the generation of high-energy short pulses from a mode-locked erbium/ytterbium-doped large-mode-area multifilament-core fiber laser operating in the purely anomalous dispersion regime. The self-starting fiber laser emits 400 mW of average output power at a pulse repetition rate of 44 MHz, corresponding to a pulse energy of 9.1 nJ. The laser produces near transform-limited output pulses with pulse duration of 1.6 ps, corresponding to 5 kW peak power. This new type of low-nonlinearity fibers demonstrates the power and energy scaling potential of fiber-based short pulse lasers in the eye-safe region. [ABSTRACT FROM AUTHOR]

Abstract: The absorption and emission properties of silica based ytterbium doped preforms, made by Modified Chemical Vapor Deposition, and of the drawn fibers were investigated as a function of the atmosphere during the preform collapsing. Under increasingly reducing conditions for the collapsing atmosphere, a strong UV/VIS absorption is built up, accompanied with an UV excited emission in the visible region, obviously induced by the formation of Yb2+ ions. Both the fluorescence lifetime of the Yb3+ lasing level and the cooperative fluorescence in the visible are remarkably diminished. Laser power experiments with the different fibers show a strong deterioration of the laser efficiency parallel to the degree of reduction of the doped glasses. [Copyright &y& Elsevier]