Technical Insight
Improved laser design pushes wallplug efficiency to 65%
Rob Williamson and Manoj Kanskar report on dramatic improvements in the power conversion efficiency of high-power laser diode bars, enabling higher-reliability devices and new applications.
High-power laser diodes, with optical output power ranging from a few watts per emitter to nearly 100 W per bar, power a wide range of laser systems and end applications. The output of these diodes can be used directly, for example for materials processing and medical applications, or to pump a wide range of other sources, such as diode-pumped solid-state lasers, fiber amplifiers and fiber lasers.
Although semiconductor laser diodes can be made with emission wavelengths ranging from ultraviolet (below 400 nm) using GaN and similar structures, all the way to the mid-infrared (beyond 3 µm) with lead-salt devices, the highest-efficiency laser structures currently known utilize III-V materials that emit from 750 to 1100 nm. These InGaAs/(In)GaAsP materials can reliably produce several watts of optical power from a 1 x 100 µm output facet. When combined in an array to form a laser bar, such devices can produce in excess of 60 W continuous-wave (CW) output, and more than 100 W in quasi-CW (
Although semiconductor laser diodes can be made with emission wavelengths ranging from ultraviolet (below 400 nm) using GaN and similar structures, all the way to the mid-infrared (beyond 3 µm) with lead-salt devices, the highest-efficiency laser structures currently known utilize III-V materials that emit from 750 to 1100 nm. These InGaAs/(In)GaAsP materials can reliably produce several watts of optical power from a 1 x 100 µm output facet. When combined in an array to form a laser bar, such devices can produce in excess of 60 W continuous-wave (CW) output, and more than 100 W in quasi-CW (
