High power laser weapons have made impressive technical progress and have demonstrated their capabilities in shooting down numerous targets in live demos. National demonstrator systems on military platforms are now in preparation, for instance the integration of a 20 kW laser effector on a maritime platform. The core component of a laser weapon system is the militarized high energy laser (HEL). In this contribution the development of a 20 kW HEL for defence application will be presented. The laser concept is based on robust, compact and efficient high-power single-mode fiber laser modules. Power scaling to 20 kW is achieved with spectral beam combining. System architecture and laser data will be discussed.
We present highly efficient three-channel dual-grating spectral beam combining with a combined signal output power of 5.5 kW at an excellent beam quality of M2 = 1.5. Three 2-kW all-fiber narrow-linewidth continuous-wave Ytterbium-doped fiber amplifiers at 1050 nm, 1070 nm and 1090 nm were combined using in-house fabricated polarizationindependent dielectric reflection gratings. The total combining efficiency was 94% at full power level, which is close to the expected value referred to the incorporated grating’s efficiency in a dual-grating setup.