Intrinsic Optical Losses of GeO2–P2O5–Al2O3Glasses for Optical Fibers

Abstract Intrinsic optical losses of GeO 2 –P 2 O 5 –Al 2 O 3 glasses considered as potential materials for low-loss optical fibers have been investigated. Rayleigh scattering (at 488 nm wavelength) and infrared absorption tailing of GeO 2 –P 2 O 5 –Al 2 O 3 glasses were measured using silica glass as a standard. Rayleigh scattering losses of 10–20 mol% P 2 O 5 –GeO 2 glasses were as low as those of pure GeO 2 glass. Addition of 1–2 mol% Al 2 O 3 improves the stability against crystallization and chemical durability with a slight increase of Rayleigh scattering. The minimum loss of GeO 2 glasses containing below 20 mol% P 2 O 5 is estimated to be 3 × 10 −2 –1 × 10 −1 dB/km, which is between the values of silica glass (∼10 −1 dB/km) and GeO 2 glass (3 × 10 −2 dB/km).