Compact Phase-Locked Fiber-Laser Array

For the Airborne Laser (ABL) and other laser-based missile defense systems to become an effective deterrent, there still needs to be significant improvements in laser power, efficiency, and stability.The proposed research will demonstrate the feasibility of developing a coherent array of fiber lasers using an extremely compact and novel external-cavity design. The resulting laser system will provide a dramatic increase in laser output capability andthus, the ability to deliver this power into a single, diffraction limited output beam. As a result of the proposed design, the system readily promises to increase in power, efficiency, and stability as the number of elements in the array increases.The proposed system will utilize a compact external cavity to coherently couple multiple laser devices together. Due to the proprietary and novel design of the compact external cavity, the system size is drastically reduced and will achieve acorresponding increase in stability.In the proposed effort, the optical design of the fiber laser array will be detailed, key components will be identified, polarization control and phase control techniques of the lasers will be specified, and a preliminary design for the full-scale laserarray generated.Coherent combination of multiple fiber lasers will enable the possibility of generating extremely high power laser outputs in a diffraction limited beam. High power lasers find numerous commercial applications in the industry with applications in themedical field, environmental monitoring, and metal cutting, welding, and engraving.