Single-crystal sapphire fibers have been grown with the laser-heated pedestal-growth method with losses as low as 0.3 dB/m at 2.94 µm. With the incorporation of a computer-controlled feedback system, fibers have been grown with less than ±0.5% diameter variation, or ±1.5 µm for a 300-µm fiber. The losses in these fibers have been reduced further through a postgrowth anneal at 1000 °C in air, from 5.4 to 1.5 dB/m at 543 nm and from 0.4–0.3 dB/m at 2.94 µm. These fibers delivered 4.7 W at 10 Hz of Er:YAG laser power.
© 1997 Optical Society of America
Original Manuscript: December 2, 1996
Revised Manuscript: April 8, 1997
Published: August 20, 1997
Rick K. Nubling and James A. Harrington, "Optical properties of single-crystal sapphire fibers," Appl. Opt. 36, 5934-5940 (1997)