In this work we represent a highly efficient (>20%) CW second harmonic generation in PPKTP and PPLN crystals. As a fundamental source we used a high power (>24W) single-frequency (<50kHz linewidth) linearly polarized CW Er:Yb fiber laser. This laser was used in a single pass schematic to achieve more than 5W average power SHG in 780nm. Single pass conversion efficiency of >20% for PPLN and >7% for PPKTP was demonstrated. We also demonstrate a possibility of single mode fiber delivery for this SHG source with excellent beam quality (M<sup>2</sup> <1.1). Pump power dependency of conversion efficiency and other SHG characteristics for PPLN and PPKTP would be presented and compared.
Super compact, 3W power, 1060 nm polarization maintaining, diode-pumped ytterbium fiber amplifier with extinction ratio greater than 17 dB and wall-plug efficiency greater than 14% have been developed. Performance of the device fits requirements of free-space and satellite optical communications applications.