Free-Space Fiber Optic Laser Rod

Langley Research Center, Hampton, Virginia

NASA's Langley Research Center has developed a compact, highly efficient, multi-purpose laser rod. This system employs a modular laser design with highly efficient and compact components. The laser consists of distinct building blocks to achieve wavelengths of 1.0, 1.5, and 2.0 microns. Amplifier modules are based on a novel hybrid fiber rod concept. By confining the otherwise highly divergent pump radiation to a small channel via total internal reflection at a moderately high numerical aperture interface, the low-brightness diodes can pump with high power density over a moderately long absorption path, thereby achieving highly efficient pump absorption.

Cross-section of a hybrid fiber rod. (NASA)

For the new laser concept, a relatively short but large core fiber doped by active lasing material is used in place of a conventional solid-state crystal as the amplifier gain media in a free-space configuration. The technology avoids the usual problems of low thresholds for catastrophic optical damage and other nonlinear loss processes in fiber lasers by increasing the fiber core diameter of a standard 9-micron, single-mode fiber to the order of 1 mm, thereby permitting peak powers to be increased by factors of 10,000. The usual degradation of single-mode propagation in large-diameter fibers is avoided by keeping fiber lengths short, thereby staying within a free-space, single-mode propagation regime.

NASA is actively seeking licensees to commercialize this technology. Please contact The Technology Gateway at This email address is being protected from spambots. You need JavaScript enabled to view it. or 757-864-1178 to initiate licensing discussions. Follow this link here for more information.