High-power 100-fs pulse generation by frequency doubling of an erbium–ytterbium-fiber master oscillator power amplifier

Frequency doubling of an erbium–ytterbium-fiber master-oscillator–power-amplifier system is demonstrated. Simultaneous amplification and pulse compression in multimode erbium–ytterbium-doped fibers produces high-quality near-diffraction and near-bandwidth-limited 100-fs pulses at a wavelength of $1.62 \mathit{\mu }\mathrm{m}$ with an average power of 230 mW at a repetition rate of 52 MHz. Periodically poled ${\mathrm{LiNbO}}_3$ allows for frequency doubling with a conversion efficiency of 51%, producing near-bandwidth-limited 105-fs pulses with an average power of 117 mW and a pulse energy of 2.3 nJ at a wavelength of 810 nm.