More than 20 W fiber-based continuous-wave single frequency laser at 780 nm

We demonstrate a 21.2Wcontinuous-wave single frequency 780 nm laser by utilizing single-pass frequency doubling of a 49.8 W 1560 nm fiber amplifier in a periodically-poled magnesium-oxide-doped lithium niobate (MgO: PPLN) crystal. The conversion efficiency of the frequency doubling reaches up to 42.6%. The high power 1560 nm Erbium-doped fiber amplifier (EDFA) is in-band pumped by a 1480 nm Raman fiber laser. Maximum output power of 49.8 W is obtained at an incident 1480 nm laser of 60.6 W, corresponding to an amplification efficiency of 79.7%. To the best of our knowledge, this is the highest reported continuous-wave single frequency 780 nm laser, which is developed for advanced quantum technology with Rb cold atoms. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement