Recent Developments In Growth Of Shaped Sapphire Crystals

The Edge-defined, Film-fed, Growth (EFG) process was chosen by the authors for continuous growth of 10 mil (250 micron) optical quality sapphire filament. Sapphire filament is capable of withstanding temperatures above the melting point of conventional fiber optics, while also resisting corrosion, and providing spectral transmission into the infrared range. The lowest transmission loss measured approached 10 dB/meter. While the EFG process has been used to grow continuous lengths of structural quality filament exceeding 100 feet, the longest continuous optical filament grown in this study was approximately 16 feet.