Efficient green-light generation by frequency doubling of a picosecond all-fiber ytterbium-doped fiber amplifier in PPKTP waveguide inscribed by femtosecond laser direct writing

Abstract

We have demonstrated an ultrashort, compact green light radiation by frequency doubling of an all-fiber ytterbium-doped fiber laser source in a PPKTP waveguide fabricated by femtosecond laser pulses. Using the fabricated PPKTP waveguide crystal containing a 10 mm single grating with a period of 9.0 μm, we generate 310 mW of picosecond radiation at 532 nm for a fundamental power of 1.6W, corresponding to a conversion efficiency of 19.3%. The temperature tuning range of 8°C is achieved for a fixed fundamental wavelength of 1064 nm, the FWHM of the wavelength tuning curve is 4.2 nm at room temperature. The generated ultrashort pulses at 532 nm are of great importance and have comprehensive applications in photobiology research and high-resolution spectroscopy.

Frequency doubling of narrow-linewidth pulsed fiber laser

“…Aculight Company has employed a high-power 1 080-nm pulsed laser via using two LBO crystals to realize the average power of a green-source output of 60 W [18] with a conversion efficiency of 54.5%, the highest reported power achieved by green-source fiber lasers. As a frequency-doubling crystal, KTP has a higher nonlinear coefficient than LBO and a stronger damage threshold than PPKTP [19] . However, reports on green lasers produced from fiber laser using the KTP crystal are scarce [20] .…”