Fiber Laser Beam Combining for High Efficiency and Light-Weight HEL Systems

Period of Performance: 09/28/2007 - 09/28/2009

$730K

Phase 2 SBIR

Recipient Firm

Aculight Corp.
22121 - 20th Avenue SE
Bothell, WA 98021
Principal Investigator

Abstract

High Energy Lasers (HELs) are required for a variety of military directed energy applications including area protection against rockets, artillery, and mortars (RAM). A typical laser enabling these applications should provide at least 10 to 100 kW of output power with excellent beam quality. Moreover, to provide maximum benefit on the modern battlefield, the HEL system should be portable, feature a high electro-optical efficiency and power-to-mass ratio, and have simple thermal management requirements. To meet these demanding specifications while overcoming the size, weight, and thermal management problems inherent to slab-based laser technology, we will demonstrate a spectrally beam combined (SBC) fiber laser system that combines the highly efficient power scaling capabilities for fiber SBC with the power-independent beam quality, high electro-optical efficiency, simple thermal management requirements, compact, modular, and flexible packaging, and fully integrated, automatic spectral control of fiber ring oscillators. To scale the power per fiber to the multi-kW level, we will also explore using polarized photonic crystal fibers (PCF), which have enhanced power handling and significantly lower nonlinear effects than standard large-mode-area (LMA) fibers. This approach dramatically reduces the number of fiber lasers, enables power scaling to the 100+ kW level, and improves system robustness.