Northrop Grumman Corporation has surpassed Phase I goals for the Defense Advanced Research Projects Agency's (DARPA) 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.
"This is an important step in the maturation of fiber laser technology," said Dan Wildt, vice president of Directed Energy Systems for Northrop Grumman's Aerospace Systems sector. "By surpassing Phase I goals, we are in an excellent position for success in Phase II. Success in Phase II will create a powerful springboard for scaling fiber lasers to weapons-class performance levels."
With a 1 kilowatt (kW) single mode fiber amplifier, the company demonstrated a near-perfect beam quality of better than 1.2 and efficiency better than 30 percent, twice the program's goal of 15 percent. 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.
The Phase I success was a team effort involving Nufern, East Branby, Conn., which supplied high-power amplifiers; Fraunhofer USA, Inc., Plymouth, Mich., 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 3kW 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 100kW, 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 25kW.