High Brightness Beam-Coupler for High Power Diode Lasers

TACOM-ARDEC has demonstrated that high brightness lasers produce highly repeatable class III black powder ignition delay times in large caliber guns. However, for the laser igniters to displace conventional primers they must be compact, lightweight,efficient, robust enough for breech-mounting and provide lower life cycle costs. Advances in laser technology are needed to meet these requirements and support deployment. High power diode bars are efficient, but their poor beam quality (typical M2>1000from a 60W bar) is incompatible with the brightness requirement for ignition. To meet the laser igniter requirements, CTI proposes an innovative, active beam-combining architecture, capable of dramatically enhancing the combined brightness (>300x) ofmultiple diode bars to generate near diffraction-limited output at multi-kW levels. In order to maintain high brightness, the beam-combiner virtually eliminates thermo-optic beam distortions and is compatible with wide temperature band operation. Phase Iproduced: (a) comprehensive modeling and engineering analyses, (b) proof-of-concept demonstrations to validate the proposed architecture, and (c) breadboard and brassboard preliminary designs. Phase II will (1) deliver a compact kW-class breadboard laser;(2) support testing of the laser on a breech simulator at Picatinny; and (3) design a rugged, air-cooled battery-powered prototype of the laser to operate with recoil on the breech of large caliber guns. CTI's proven ability to engineer rugged,electro-optic systems for high shock, vibration and temperature range environments provides leverage for a successful overall development program.Anticipated applications include (1) ignition systems for munitions and explosives, (2) high power laser foraerospace-platform missile defense, (3) low cost, active LADAR sensors for industrial and military markets (4) cost-effective laser sources for materials processing, printing, and medical applications. High power lasers have the potential commercial appealin the high power laser market that fiber lasers have in the low power market.