Abstract

Single-crystal fibers of Nd:YAG, Nd:Y₂O₃, ruby, sapphire, LiNbO₃, and LiTaO₃ were pulled (in diameters from 15 to 100 µm) from a tiny melt obtained by heating the tip of a thin rod of the parent crystal in air with the focused beam of a CO₂ laser. Short Nd:YAG fibers, some with a fused-glass cladding, were made into lasers by attaching suitable dielectric mirrors to the ends and end pumping with a single 0.8-µm wavelength AIGaAs LED. Laser output was obtained at 1.06-µm and 1.318-1.338-µm wavelength. Up to 1 mW of single-mode output power, limited primarily by imperfect coupling between the LED pump and the fiber laser, was measured. Similar laser structures made with Nd:Y₂O₃ and ruby were pumped with a krypton gas laser. The thermal efficiency of the fiber geometry both promoted homogeneous crystal growth and permitted cw laser operation, and all devices could be operated cw at room temperature. LiNbO₃ and LiTaO₃ fibers were grown for possible use as modulators. The crystalline orientation of any of the fibers could be predetermined by selecting the seed orientation, and some resultant growth habits are shown. In general, since the growth process inherently involves zone refining, single-crystal fibers are of very high purity and optical quality.

© 1985 Optical Society of America