Widely tunable sum-frequency generation in PPLN waveguide pumped by a multi-wavelength Yb-doped fiber laser

We present some experimental results on tunable sum-frequency generation in a periodically poled lithium-niobate waveguide using a multi-wavelength fiber laser pump stabilized by a nonlinear optical loop mirror. We are able to up-convert to about 629 nm a continuous-wave infrared signal varying from 1497 nm to 1525 nm. Such a wideband conversion efficiency is ensured by the multiple spectral components of the laser pump, which is controlled by an adjustable Fabry–Perot filter. Potential applications, in particular for stellar imaging, are discussed.