SBIR-STTR Award

Very high power can be obtained by combining a large number of diode laser bars, but unfortunately the combined output consists of a very low-brightness beam with very large beam divergence, therefore, it is unsuitable for igniting large caliber guns. PC Photonics is proposing a diode-pumped multicore fiber laser array, which is capable of delivering very high power in a high-brightness beam emitting from an aperture of ~30 microns, in which the power density is sufficient to ignite large caliber guns. By phase-locking 7 Yb-doped single-mode fiber lasers in a common cladding, PC Photonics has obtained a high-brightness laser beam by clad-pumping this fiber laser array with a multimode diode laser. The optical to optical conversion efficiency is 87 %. Under Phase I, PC Photonics will use the highest professional standard to design a high energy laser, which will meet Army Crusader's requirements with a great deal of confidence. Under Phase I-Option, preliminary experiments will be performed to demonstrate a unique technique for efficient pumping of the double-clad fiber at very high power level. High power diode-pumped multicore fiber lasers can be very competitive in the market place as compared to high power diode-pumped solid-state lasers and CO2 lasers presently employed by automobile, aerospace and heavy manufacturing industries for precision welding, cutting and drilling of metallic and composite materials. Other applications include laser printing, bar coding, inspection, dental and medical surgery.

This Phase II-SBIR proposal is directed toward developing an affordable high-energy fiber laser for the US Army Arsenal for igniting large caliber guns. The proposed laser is a diode-pumped, double-clad, Yb-doped multicore fiber array arranged in two isometric rings, which are embedded in a very large cladding having a very large NA, so that a pump laser with fairly large beam spot can be injected efficiently into the inner cladding from the side-wall along the length of the fiber. Under this Phase II-SBIR, a prototype will be built, packaged, characterized and delivered to the Army. The goal of this project is to demonstrate a reliable and maintenance-free high-energy fiber laser, emitting a high-brightness and diffraction-limited beam with an output power greater than 200W in a spot size of about 50 microns. Through this effort, not only a high-energy fiber laser will be developed specially for the Army's application, but also a sound foundation will be laid for commercializing an affordable industrial laser, which will provide a high-brightness output in the power range from 100W to 1,000W for a variety of industrial applications.Diode-pumped multicore fiber laser can provide very high output power with a high-brightness and diffraction-limited beam at an affordable cost. It is therefore very competitive in the market place as compared to diode-pumped solid-state lasers and CO2 lasers presently employed by the industries for high speed and precision manufacturing.

Keywords:
fiber laser, double-cladding, supermode, high power, multicore, phase locking, uni-phase, high-brightness