Glass-fiber waveguide with losses below 1 dB/km

Glass-fiber waveguides with minimum losses of 0.7 dB/km at λ = 1.6μ were developed. These waveguides were made by chemical precipitation from the vapor phase. The core material was SiO₂ + GeO₂ and the cladding was made of SiO₂. The numerical aperture was 0.28. The losses were as follows: 1 dB/km at λ=1.2μ, 2 dB/km at λ=1.06μ, and 5 dB/km at λ = 0.82μ. The possibility of fiber-optical communication in the wavelength range 1.1–1.7μ was considered.