Nearly Diffraction-Limited Tapered Lasers at 675 nm With 1-W Output Power and Conversion Efficiencies Above 30

High brightness, highly efficient tapered lasers emitting around 675 nm have been developed. The devices have a 500- μm-long straight section and a 1500-μm -long tapered section with a flare angle of 3°. At a temperature of 25°C and a current of 1.5 A, the lasers emit an output power of nearly 1.2 W. The maximum conversion efficiency of 31% is reached at an output power of 1 W. The emitted beam is nearly diffraction-limited with a beam propagation ratio (second moments) of 2.2.