A diode laser having a plurality of layers including a thin (e.g., about 0.3 m or less) p-type cladding layer, the plurality of layers having a substantially asymmetric refractive index profile with respect to the layer growth direction to produce an optical field distribution with a larger fraction of the distribution in n-type layers than in p-type layers of the laser. The layers can be configured to produce a ridge diode laser having an internal loss less than about 3 cm^-1, and able to generate an approximately 980 nm laser beam with a transverse divergence of about 28 or less, and a spot size of about 0.8 m or more.