ARLINGTON, Virginia – US military investigators ask Northrop Grumman Corp. to develop affordable high-energy laser sources for future laser weapons that can destroy or disable enemy unmanned aerial vehicles (UAVs).
Officials at the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Virginia, have announced a two-year, $7.8 million contract with Northrop Grumman in Redondo Beach, California, for the Modular Efficient Laser Technology (MELT) program.
MELT aims to develop a compact, scalable, active coherent beam combined semiconductor laser source with excellent beam quality to create a mass-producable, low size, weight, and power (SWaP) scalable laser source.
MELT aims to take advantage of technologies such as semiconductor fabrication techniques, coherent beam combination, photonic integration and 3D integration and packaging.
Today laser weapons that use multiple beam-combined high-power fiber amplifiers as the high-energy laser sources, as well as large complex optical subsystems that condition and project the laser beam, don’t scale well, DARPA researchers say.
On the other hand, high energy laser sources with coherent beam combined tile array are scalable because they eliminate these large subsystems.
Cohesive beam-combined tile arrays provide a path to better high-energy laser sources due to the ability to directly generate and project the laser beam without bulk optics; the intrinsic scalability of a tiled array with no inherent limits; the ability to perform non-mechanical beam steering for beam jitter corrections; and the ability to apply complex phase corrections to compensate for atmospheric disturbances.
The proliferation of small, cheap unmanned aircraft (UAVs) on the battlefield require layered defense with low cost laser weapons. The deep magazines of laser weapons are suitable for countering swarms of hostile UAVs and have the potential to achieve very low operating costs, assuming low production costs can be achieved. Counter UAV and similar applications require a wide range of power levels from a few kilowatts to megawatts, which is not possible today.
Instead, MELT is trying to develop a laser tile as a building block for compact, scalable paneled laser weapons. The laser tiles will be integrated into planar arrays for scalable laser weapons with comparable or better performance than current laser weapons.
MELT aims to demonstrate a series of 3 by 3 panel laser tiles with excellent beam quality as a scalable high energy laser source.
The mass, volume, and size objectives for the laser tile and laser tile panel array include the semiconductor amplifier emitters, optics, phase sensing and control, power delivery, power conversion, thermal dissipation, computing, remote connections, electrical intertiles, coolant, and data connections.
Each MELT tile will contain a 2D array of laser emitters whose phase can be continuously observed and controlled to achieve coherent beam combination. For scalable output power, several to several hundred of these tiles can be arranged as a panel-mounted, gimbal-mounted laser weapon source that produces a usable output beam.
The DARPA MELT project has three technical challenges: a dense planar tiled array of amplifiers with uniform spacing and emission perpendicular to the 2D surface; realizing a scalable phase-detection architecture for a high-energy panel laser source; and realizing a compact, scalable cooling solution to remove the expected thermal load from a high energy panel laser source.
The goal of this program is to develop a mass-producable, low SWaP, scalable laser source. This requires the development of a new type of high-energy laser source. The MELT program is only interested in semiconductor diode based laser technologies that do not include optically pumped brightness converters.
Under the contract, Northrop Grumman will do the work in Redondo Beach and Goleta, California, and should be completed in October 2024. For more information, contact Northrop Grumman online at www.northropgrumman.com/what-we-do/air/directed-energyor DARPA on www.darpa.mil/program/modular-efficient-laser-technology.