Laser Diodes:

Sandra Todd, Coherent Inc., Santa Clara, Calif.

In recent years, the demand for high-power laser diodes, bars and arrays has grown rapidly. Most of the applications for these near-infrared devices can significantly benefit from a combination of higher output power and longer lifetime.
In traditional AlGaAs laser diodes, the presence of aluminum in the active junction ultimately limits these performance parameters. In response to this problem, researchers developed "aluminum-free" laser diodes based on the InGaAsP material system.
InGaAsP offers several advantages over AlGaAs for laser diode users, but commercial manufacturers have had to overcome many technical hurdles before developing the current reliable volume manufacturing of a new generation of Al-free lasers. These latest devices not only deliver higher power with longer lifetimes, but also have much lower output divergence, which means more focusable output.

AlGaAs Diodes Still Solving
Customers' Problems
by John Tracy, Opto Power Corp.

Customers only care about solutions to their problems, not about esoteric debates over technological fine points such as material composition. Markets for high-power diode lasers have grown because of the success of AlGaAs-based products that have met a range of pragmatic requirements. Included in these pragmatic requirements are, of course, lifetime and degradation rates.

AlGaAs Diodes Offer High
Power, Reliability
by S. O'Brien and B. Li, SDL Inc.

High-power, multimode diode lasers are well-suited for a diverse set of applications including telecommunications, printing, diode-pumped solid state fiber- and crystal-based materials, medical and materials processing. Because of their higher thermal load and larger area, the performance of cw multimode lasers is a critical test of the material quality and the reliability of a semiconductor material system. AlGaAs can produce very high-quality crystalline layers and, consequently, very high-quality diode lasers. Additionally, AlGaAs materials provide excellent electrical and optical confinement, and electrical and thermal conductivity.