Yoshikazu Kaite

Optical transmission properties of low loss-large numerical aperture glass fibers made by the double-crucible technique

Abstract Optical glass fibers with a very large numerical aperture (NA) of 0.56 and a loss of 8.6 dB km −1 have been fabricated by the double-crucible technique using multicomponent glasses. A large numerical aperture (NA) of over 0.5 brings about effective light couplings with conventional LED sources, and a relatively low loss of less than 10 dB km −1 easily extends the span of optical transmission systems such as data transmission, remote sensing, telemetering, etc. to more than 1 km. Optical transmission properties of the fibers including spectrum losses, scattering losses, coupling losses and connection losses are reported.

Compound glass fiber waveguides with a wide core and a large numerical aperture

Abstract Large numerical aperture and large core diameter fibers are made from compound glasses without difficulty using the double crucible technique. Moreover, compound glass fiber waveguides have suitable properties for industrial production in large quantities. Compound glass fiber with medium loss provides economical components for producing optical short distance communication line and other optical devices as applied in several aspects of industrial process control and measurement. The glass compositions, the fabrication technique, and the practical data concerning such properties as fiber to fiber connection, fiber to light source coupling, temperature dependence of transmission loss and water-resistance are briefly discussed.