Research on ytterbium-doped photonic crystal fiber amplifier for the femtosecond fiber laser

Abstract

We report on a single-stage, high-repetition photonic crystal fiber amplifier working at 1030 nm seeded by a femtosecond fiber laser, which generates an output with average power of 2.23 W at a repetition rate of 49.5 MHz and a 3 dB spectral width of 5 nm, corresponding to a pulse energy of 45.2 nJ. After amplification, the spectrum of the femtosecond laser is broadened. A home-made, ytterbium-doped, double-clad photonic crystal fiber fabricated by laser sintering technology combined with a solution doping method with a core diameter of only 24 μm is used as the power amplifier medium. The spectral characteristics as well as the suppression of amplified spontaneous emission are discussed in detail. Experiment confirms that the amplified spontaneous emission becomes negligible with increasing incident seed power and no obvious nonlinear effects arise in this experiment. These results can provide motivation for the application of ytterbium-doped photonic crystal fiber and can provide a potential application for the high-power, all-fiber laser in the future.