Chalcogenide Glass-Fiber-Based Mid-IR Sources and Applications

The Naval Research Laboratory (NRL) is developing chalcogenide glass fibers for applications in the mid- and long-wave IR wavelength regions from 2 to 12 mu m. The chalcogen glasses (i.e., glasses based on the elements S, Se, and Te) are transparent in the IR, possess low phonon energies, are chemically durable, and can be drawn into fiber. Both conventional solid core/clad and microstructured fibers have been developed. Chalcogenide glass compositions have been developed that allow rare earth doping to enable rare-earth-doped fiber lasers in the IR. Also, highly nonlinear compositions have been developed with nonlinearities similar to 1000 x silica that enables nonlinear wavelength conversion from the near IR to the mid- and long-wave IR. In this paper, we review rareearth-doped chalcogenide fiber for mid- and long-wave IR lasers, and highly nonlinear chalcogenide fiber and photonic crystal fiber for wavelength conversion in the mid- and long-wave ER.