Low-loss, high-purity (TeO2)0.75(WO3)0.25 glass

Abstract

By melting a mixture of high-purity oxides in a platinum crucible under flowing purified oxygen, we have prepared (TeO 2 ) 0.75 (WO 3 ) 0.25 glass with a total content of 3 d transition metals (Fe, Ni, Co, Cu, Mn, Cr, and V) within 0.4 ppm by weight, a concentration of scattering centers larger than 300 nm in size below 10 2 cm −3 , and an absorption coefficient for OH groups (λ ∼ 3 μm) of 0.008 cm −1 . The absorption loss in the glass has been determined to be 115 dB/km at λ = 1.06 μm, 86 dB/km at λ = 1.56 μm, and 100 dB/km at λ = 1.97 μm. From reported specific absorptions of impurities in fluorozirconate glasses and the impurity composition of the glass studied here, the absorption loss at λ ∼ 2 μm has been estimated at ≤100 dB/km. The glass has been drawn into a glass-polymer fiber, and the optical loss spectrum of the fiber has been measured.