Anamorphic Microlens Coupling Between Tapered Amplifier and Planar PPLN Waveguide

We designed an aspheric anamorphic microlens for coupling between a tapered amplifier with a length of 3 mm and a planar-waveguide second-harmonic-generation device consisting of a periodically poled MgO-doped lithium niobate crystal core with a thickness of 3 μm. A coupling efficiency of 35% and corresponding green light generation with a power of 65 mW and conversion efficiency of 7.4% was experimentally demonstrated.