150 kilowatt Solid State combat laser is ready this year

The General Atomics 150-kw Hellads (high energy laser) will be tested this summer at White Sands Missile Range in New Mexico The third generation solid state laser is to be demonstrated in 2018 on the USS Paul Foster, a decommissioned Spruance-class destroyer that now serves as the U.S. Navy’s ship-defense test vessel at Port Hueneme in California.

The Gen 3 (third generation laser) has increased electrical-to-optical efficiency, improved beam quality and further reduced size and weight.

The module includes high-power-density lithium-ion batteries, liquid cooling for the laser and batteries, one or more laser unit cells and optics to clean up and stabilize the beam before it enters the platform-specific beam-director telescope, says Davis.

The unit cell is a laser oscillator that produces a single 75-kw beam. Modules can be ganged together to produce a 150- or 300-kw beam. There is no beam-combining, Davis says, as there is in systems that use multiple lower-power fiber lasers.

The Pentagon and several other manufacturers have shifted focus to fiber lasers because they are a commercial technology and have higher electrical-to-optical “wallplug” efficiency than diode lasers previously demonstrated at power levels exceeding 100 kw.

The Gen 3’s efficiency is at the level of fiber lasers, Davis says, adding that the company has worked for several years to improve beam quality and achieved “excellent quality” in the latest tests. Adaptive optics adjust the beam to compensate for atmospheric distortion.

Mockup shows one 75-kw laser unit cell (gold), although the tactical module has room for two, for a 150-kw laser weapon. Credit: Graham Warwick/AW&ST

“Fiber lasers are interesting, but it is a matter of maturity,” says Davis. “We are where fiber may be in five years. We have built several versions of this laser over the last 10 years, and we believe [the Gen 3 system] is affordable as is.”

In addition to the ONR program, GA-ASI is eyeing the U.S. Army’s Boeing High Energy Laser Mobile Demonstrator (HEL MD). Live-fire tests of the HEL MD used a 10-kw industrial fiber laser and the Army intends to upgrade the system to a 60-kw Lockheed Martin fiber laser.

The next step is a 120-kw laser, planned for testing in the early 2020s, and for which GA-ASI plans to propose the Gen 3 system. The Air Force Research Laboratory, meanwhile, is interested in a podded laser weapon, although there is no formal program yet.

Davis says the Gen 3’s size enables an airborne laser module in the 150-kw range to be carried by GA-ASI’s Avenger unmanned aircraft. The UAV has sufficient onboard power to recharge the module’s batteries in flight.

SOURCE – Aviation Week

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