A Cost-Effective Automatic Balloon Launcher

Not Available Over 35 W of power can be generated by a single fiber laser in a coherent, diffraction-limited beam, with a high quantum efficiency over 85%. The output power of a single fiber laser is however limited by intrinsic non-linear effects. We propose to coherently combine several fiber lasers in order to overcome such limitation. This work will build upon work by Rediker and Leger, and on the large effort in the computer field to have efficient fan-out of a laser beam. We will use a fan-in continuous phase grating to recombine the laser beams. Combination efficiency over 95% can theoretically be achieved for 3 beams, and over 99% for 9 beams. We will use our Excimer laser ablation system to fabricate the continuous phase grating in a 16-level approximation, thus allowing a quick turnaround for prototyping. The performance of the phase grating will first be evaluated in a fan-out configuration, and then in a fan-in configuration with a single fiber laser split into three beams. Three individual low-power fiber lasers will then be coherently combined. The coherence will be quantitatively evaluated and the influence of the individual fiber laser characteristics, such as frequency stability, will be analyzed in details.