Generation of high energy 780 nm femtosecond pulses by frequency doubling of an all-polarization-maintaining Er-doped fiber laser

We demonstrate a high-energy 780 nm wavelength band femtosecond laser by utilizing single-pass frequency doubling all-PM Er-doped fiber amplifier (EDFA) in a periodically-poled lithium niobate (PPLN) crystal. The high power 1560 nm laser is realized based on chirped pulse amplification (CPA) technology, which has obtained the average power of 3.02 W, repetition frequency of 1.03 MHz, and pulse width of 640 fs. Subsequently, by using a PPLN crystal as frequency doubling element, a maximum output power of 0.46 W with 620 fs pulse width at 780.29 nm is generated, the corresponding pulse energy is 0.44 μJ and the peak power is 0.71 MW. To the best of our knowledge, the 0.44 μJ laser output in 780 nm wavelength band is the highest pulse energy generated from a frequency doubling femtosecond Er-doped PM fiber laser.