Power diodes take center stage at Photonics West
The latest developments in high-power laser diodes for industrial applications were very much on the agenda at Photonics West as the annual show got underway in San Jose, California.
The high-power diode laser session kicked off with US firm Alfalight unveiling details of a 970 nm single emitter that can pump out 22 W in continuous wave (CW) mode at 25°C.
Alfalight claims that its record-breaking 100 µm single-stripe chip, which was bonded p-side down on a copper heatsink, had a peak power-conversion efficiency (PCE) of 68%.
The Madison, WI, company is working towards reaching the 80% PCE target set by DARPA under its super high efficiency diode sources (SHEDS) program, and its recent efforts include a PCE of 71% at 25°C from a 20% fill-factor bar.
Giving a flavor of things to come, fellow US firm nLight projected that there are no fundamental barriers to achieving a peak power of 1 kW from a single 1 cm diode laser bar.
Having already demonstrated output in excess of 400 W from single bars emitting at 800 nm, the Vancouver, WA, company believes that advances in efficiency as well as reductions in the diode s operating voltage and the thermal resistance of its packaging will drive the output powers to higher levels.
Meanwhile, Jenoptik claims to have broken the 500 W barrier with a 1 cm diode laser bar producing 509 W. The latest benchmark is the result of improved mounting techniques, says the German firm.
Coherent took to the stage at the packed LASE session to present details of its work on high-efficiency, high reliability 9xx nm diode laser bars in both conductively cooled packages (CCP) and fiber array packages (FAP). Having developed 980 nm bars with a PCE of 71.5% in the lab, the company hopes to release 9xx nm 60W FAPs and 80-100W CCPs in the near future.
Not to be outdone, JDSU, which is much better known for its supply of laser diodes for telecom applications, introduced a new industrial laser system at the event.
The system uses single-emitter sources to deliver up to 100 W into a solitary output fiber.
JDSU claims that the single emitters have the advantage of a much greater lifetime than diode bars becuse the technology has had to prove itself in highly-demanding telecom applications.
The San Jose company is touting its system for applications such as laser soldering and plastic welding.
Author
Jacqueline Hewett is technology editor on Optics.org and Opto & Laser Europe magazine.
