Generation of high-power 780 nm femtosecond pulses by an all-polarization-maintaining Er-doped fiber amplification system

A 187 fs pulse laser with 2.3 W of output power at 1560 nm is built for second-harmonic generation (SHG), which is the highest average power output reported from an all-polarization-maintaining single-mode Er-doped chirped pulse amplification system. By subsequently using an MgO-doped periodically poled lithium niobate (MgO:PPLN) crystal as frequency doubler, a 183 fs pulse laser with 1.1 W output power at 778 nm is generated. Benefitting from a polarization-stable fundamental laser input and the temperature control of the PPLN crystal, the power fluctuation of the frequency doubled laser is less than 0.5% during 24 h. To the best of our knowledge, the 1.1 W output at 780 nm band is also the highest average power generated from a frequency doubled femtosecond Er-doped fiber laser.