Aluminum-free diode bars produce 40-W continuous-wave output at 808 nm
Aluminum-free diode-laser bars emitting u¥to 40-W CW output power at 808 nm were reported by M. Jansen and others from Coherent (Santa Clara, CA, and Tampere, Finland) at CLEO `98 (San Francisco, CA). Unlike other aluminum-free designs, the Coherent device has no aluminum in the active region or the waveguide layer but does include it in the cladding layers to limit carrier leakage. The active region is a single indium gallium arsenide phosphide quantum well clad with indium gallium aluminum phosphide. This design has a variety of other advantages, explained Jansen, including the ability to withstand higher temperatures before catastrophic damage, lower facet temperatures, lower series and thermal resistance, and a higher manufacturing yield than other aluminum-free designs.
The bars measure 1 mm by 1 cm and include 19 broad-area emitters, each 150 µm wide, on 500-µm centers. They are mounted on heat sinks and are conduction-cooled. Typical power-conversion efficiency is 52% when driven at 50 W. Lifetime measurements suggest a mean time between failures of 16,000 h, with a 60% confidence level when operated at 40°C. The bars were introduced commercially at CLEO `98.