Northrop Grumman surpasses fiber-laser goals, receives phase II contract from DARPA

Redondo Beach, CA--Northrop Grumman Corporation has surpassed Phase I goals for the Defense Advanced Research Projects Agency's (DARPA's) Revolution in Fiber Lasers (RIFL) program that seeks to mature fiber-laser technology. As a result, the company has received a contract for Phase II.

"Success in Phase II will create a powerful springboard for scaling fiber lasers to weapons-class performance levels," said Dan Wildt, vice president of Directed Energy Systems for Northrop Grumman's Aerospace Systems sector.

With a 1 kW single-mode fiber amplifier, the company demonstrated a near-perfect beam quality (M²) of better than 1.2 and efficiency better than 30%, twice the program's goal of 15%. Northrop Grumman also demonstrated a polarization-extinction ratio of 50:1 and extremely low phase noise, which is essential for the coherent combination of laser chains used to scale power to weapons-class levels.

Team effort
The Phase I success was a team effort involving Nufern (East Granby, CN), which supplied high-power amplifiers; Fraunhofer USA (Plymouth, MI), which supplied high-power diode laser pumps; and the Johns Hopkins University Applied Physics Laboratory (Laurel, MD), which supplied advanced fiber design and analysis.

The $4.6 million, 18-month Phase II DARPA contract calls for scaling power to 3 kW in a single-mode fiber amplifier. The company has patents on techniques used to facilitate combination of many fiber amplifier beams, while maintaining near-ideal beam quality. The ultimate goal is to develop the technology to 100 kW, the power necessary to field a lethal laser weapon.

Northrop Grumman is also working on other laser initiatives that will build on the company's scalable architecture and beam-combining expertise. They include:

--The 2-Dimensional Diffractive Optical Element Beam Combining Demonstration, a U.S. Air Force Research Laboratory program under which the company is demonstrating diffractive beam combining using the Joint Department of Defense high-power fiber laser test bed, and

--The Robust Electric Laser Initiative, a two-year, $8.7 million contract for a High Energy Laser -- Joint Technology Office program to produce a design using the company's diffractive-optical-element beam-combining technique to increase power levels to 25 kW.