US Patent 7944958 Pulsed laser light source based on frequency conversion

A light emitting device including a waveguide having an electrically pumped gain region, a saturable absorber, a nonlinear crystal, an inclined mirror, and a light-concentrating structure. Light pulses emitted from the gain region are reflected by the inclined mirror and focused by the light-concentrating structure into the nonlinear crystal in order to generate frequency-converted light pulses. The gain region, the saturable absorber, the light-concentrating structure and the inclined mirror are implemented on or in a common substrate. The resulting structure is stable and compact, and allows on-wafer testing of produced emitters. The folded structure allows easy alignment of the nonlinear crystal.