High power red to mid-infrared laser source from intracavity sum frequency optical parametric oscillator pumped by femtosecond fiber laser

A femtosecond laser source tuned from red to mid-infrared is demonstrated. It is based on intracavity sum frequency generation of a MgO-doped periodically poled LiNbO₃ optical parametric oscillator synchronously pumped by modelocked Yb large-mode-area photonic crystal fiber, which has high average power and high repetition rate. The optical parametric oscillator has a wide spectral tuning range from 1450-2200 nm (for the signal) and 2250-4000 nm (for the idler) while the wavelength of the pump is 1040 nm. In the experiment, the output power of 374 mW at 1502 nm is achieved when the pump power is 2 W and the slope efficiency is 18.7%. In addition, 166 mW idler at 3.4 _m are achieved. By using a β-BaB₂O₄ for intracavity sum frequency generation, the femtosecond pulse over 610-668 nm is obtained. A 694 mW average output power of sum frequency generation is achieved for 4.1 W pump, representing 16.9% conversion efficiency at 615 nm.