TRANSMISSION LOSS CHARACTERISTICS OF TELLURIDE-BASED CHALCOGENIDE GLASS OPTICAL FIBERS

Transmission loss characteristics of Ge-Se-Te ternary chalcogenide glass optical fibers are investigated. It is found that there is a broadband transmission loss at wavelengths between 2 and 10 mum, which greatly affects the loss at 10.6 mum (CO2 laser emission wavelength). This broadband loss increases exponentially with the Te content, and is inversely proportional to the third power of the wavelength. Furthermore, the glass is found to contain hexagonal Te microcrystals. These results indicate that the broadband loss originates from the Mie scattering due to hexagonal Te microcrystals whose diameters are estimated to be 0.2 mum. Therefore, it is found that to obtain low-loss Te-based optical fibers it is essential to eliminate the hexagonal Te microcrystals.