High-power reliable aluminum-free lasers

Summary form only given. Aluminum-free laser diodes emitting at wavelengths from 800 to 1100 nm, prepared by metal-organic chemical vapor deposition, gas-source molecular beam epitaxy, and all-solid-source molecular beam epitaxy (SS-MBE), are a debated issue. The main question is the lifetime performance that is not yet explored well enough, owing to the lack of availability of these lasers. The potential advantages of Al-free lasers over their Al-bearing counterparts have been widely discussed. GaInP replacing GaAlAs in the cladding layer has good electrical and thermal conductivity. Its non-radiative surface recombination velocity is comparatively low. The concentration of donor related deep levels is small, and the unpassivated mirror facets are not easily oxidized. The corner stone of the Al-free technology is the 980-nm laser developed for pumping light into Er-doped optical fiber amplifiers. Its short-term and long-term reliability is impressive. The 808-nm laser as a pump source for Nd:YAG and Nd:YVO/sub 3/ solid-state-lasers is another important application. High output power of 100 W under cw operation from a 1 cm Al-free laser bars and over 5 W from a single 150-/spl mu/m wide stripe laser grown by SS-MBE have been demonstrated. This Al-free material shows excellent uniformity of laser characteristics across the wafer, which results in high yield of devices. Adding Al in the cladding layer of an Al-free-active-region 808-nm laser has yielded encouraging results.