High-energy all-fiber femtosecond burst laser delivering 158 μJ, 148 fs at 1 kHz repetition rate

We report a high-energy femtosecond chirped pulse amplification burst laser system based on a strictly all-fiber structure. The system consists of a mode-locked fiber oscillator, a pulse stretcher, an acoustic-optic modulator, three fiber amplifiers, and a compressing grating pair. The pulse repetition frequency is set as 1 kHz. The synchronous pump amplification technology suppresses the amplified spontaneous emission and heat accumulation. The dispersion-adjustable chirped fiber Bragg grating is used as a pulse stretcher, and the high-order dispersion in the system is accurately compensated. When the repetition frequency is set to 1 kHz and the number of bursts is 3, laser pulses with a pulse duration of 148 fs and a pulse energy of 158 µJ are obtained, with a high energy long-term stability and a good beam quality. This system has very low heat accumulation, so no cooling structure is introduced, with a good beam quality of 1.15 M² factor.