An all-fiber low-repetition-rate SESAM mode-locked fiber oscillator combined with a dispersion-managed active fiber loop produces a flexible GHz burst-mode laser source. The high-power output is then produced by amplifying the GHz burst-mode laser source using an all-fiber chirped-pulse amplification system. Then, the laser is compressed using a grating pair compressor; a maximum amplified power of 97 W is obtained. This results in a compressed high power of 82.07 W with a power stability RMS of 0.09% and beam quality better than 1.2. Accurate dispersion control allows for the production of a high-quality pulse duration of 265 fs.

We demonstrate a strictly all-polarization maintaining, all-fiber chirped pulse amplification of ultrashort pulses. Pulses with the duration of 933 fs and energy as high as 50 μJ are achieved at 200 kHz repetition rate in a compact size. The variations of the spectra and pulse widths as functions of the amplified output power have also been presented. To our best knowledge, this is the highest energy extracted from the strictly all-fiber chirped pulse amplification system. The environmentally stable femtosecond laser source will find various applications in practice.

A hybrid chirped pulse amplification system composed by the monolithic fiber pre-amplifier and a two-stage single-pass single crystal fiber amplifier was demonstrated. A maximum power of 68 W at the repetition rate of 100 kHz was obtained. The laser pulses were amplified and then compressed using a 1600 line/mm grating pair compressor. A short pulse duration of 358 fs and a power of 54 W were obtained at 100 kHz, corresponding to a peak power of 1.508 GW, to the best of our knowledge, this is the highest peak power ever obtained from single crystal fiber at repetition rate above 100 kHz due to the consideration of the third order dispersion which was engraved in the stretcher and the tuning capacity of higher-order dispersion compensation of chirped fiber Bragg grating. Additionally, the beam quality better than 1.3 was obtained. This high peak power CPA system with excellent comprehensive parameters will find various applications in scientific research and industrial applications.

A laser master oscillator power amplifier (MOPA) system consisting of a fiber amplifier and a two-stage Yb:YAG single crystal fiber (SCF) is experimentally studied. The nonlinear stimulated Raman scattering (SRS) is avoided by limiting the output power of the fiber preamplifier to 600 mW. Due to the benefit from the low nonlinearity and high amplification gain of the SCF, a laser pulse duration of 16.95 ps and a high average power of 41.7 W at a repetition rate of 250 kHz are obtained by using a two-stage polarization controlled double-pass amplification of Yb:YAG SCF, corresponding to an output energy of 166.8 μJ and a peak power of 9.84 MW, respectively. The polarization controlled SCF amplification scheme achieved a gain as high as more than 69 times. During the amplification, the spectra gain narrowing effect and the polarization controlled four-pass amplification setup are also studied. The laser spectrum is narrowed from over 10 nm to less than 3 nm, and the pulse width is also compressed to hundreds of femtosecond by dechirping the laser pulse. This compact-sized, cost-effective laser source can be used in laser micromachining, or as the seeder source for generating much higher power and energy laser for scientific research. For some applications which need femtosecond laser, this laser source can also be compressed to femtosecond regime.

The setup of nonlinear pulse compression with hollow-core photonic crystal fiber (HC-PCF) is demonstrated. In our experiment, the HC-PCF is just put in the air with no extra gas fill. The spectrum is effectively broadened to more than 60 nm by delivering the ultrashort laser in the HC-PCF and compressing the pulse with Gires-Tournois interferometer-type dispersion mirrors. The initial pulse duration of 279 fs has been shortened to 36 fs with 20μJ of pulse energy, which corresponds to a peak power of about 556 MW. To our best knowledge, it is the highest peak power obtained from the solid-state laser at the wavelength around 1 μm by using Kagome-type HC-PCF without extra gas fill. With precise dispersion compensation and higher input pulse energy, even shorter pulse width and higher peak power can be obtained.