Improved brightness using tapered diode lasers

The combination of a tapered structure and a ridge-waveguide structure is a promising design for applications, which depend on both high power and high brightness. Using this combination, we achieved an optical output power of up to 4 W in continuous wave mode (cw) and 11.6 W in quasicw mode. The wall plug efficiency reaches 42% at a current of 4 A. The beam quality parameter M/sup 2/ remains nearly diffraction limited up to about 3.5 W with values below 1.3 resulting in an improved brightness of more than 260 MW/(cm/sup 2/sr).