The US Naval Research Laboratory has developed high-power fibre lasers, which can be combined to form the basis of a high-energy laser system for directed energy (DE) weapons and power beaming.
The incoherent combined fibre laser system is currently being deployed onboard selected navy ships temporarily, following successful completion of trials by NRL Directed Energy Physics senior scientist Phillip Sprangle at the Starfire Optical Range, Kirtland Air Force Base, New Mexico, US.
During the trials, four fibre laser beams were overlapped using a beam director consisting of individually controlled steering mirrors and successfully transmitted continuous-wave power levels of 3kW at a range of 1.2km with propagation efficiencies of 90% in moderate atmospheric turbulence.
The testing began in early 2008 and validated the combined fibre laser model at long-range, quantified thermal blooming effects, and more precisely, characterised beam spread.
"It does not require phase locking or polarisation locking of the individual lasers and can be readily scaled up to a compact and reliable directed energy system," said Sprangle.
In addition to serving as all electric, instantaneous long-range targeting and delivery system, the cost-effective lasers also meet next-generation integrated power systems (NGIPS) platforms requirements, essential for next-generation all-electric ships.
Combining high-power fibre lasers offers highly efficient, compact, robust, low-maintenance, and long-lifetime high-energy laser, which can be used for applications such as shipboard missile defence, small craft defence, and power beaming to unmanned aerial vehicles (UAVs).
The Office of Naval Research (ONR) and the Joint Technology Office (JTO) have sponsored the development of the directed energy system, intended to increase the US Navy's efficiency, safety and other capabilities.
Image: US NRL performs fibre lasers experiments using a beam director. Photo: courtesy of US Naval Research Laboratory.