| 摘要 |
PURPOSE:To obtain infrared ray fiber causing low transmission loss also in an infrared ray region nor causing deterioration of transmission characteristics due to bending of fiber or contamination of the surface by prepg. glass fiber wherein the content of Ge in the central part of fiber prepd. by vitrifying a mixture of chalcogen with Ge is made higher than the same in the peripheral part. CONSTITUTION:A step index type infrared ray fiber 4 comprising Ge, with S, Se, Te, etc. as components, such as Ge-S infrared ray fiber comprises a core 5 having circular sectional shape in the central part and a clad 6 having toroidal sectional shape converting the external periphery of the core. The compsn. of the core 5 is Ge40S60 and the compsn. of the clad 6 is Ge25S75 by mol% and the refractive index of the core is ca.10mu being larger than the same of the clad. The fiber is prepd. by prepg. two kinds of Ge-S glass bar having different Ge content. A circular hole is formed at the center of a bar having smaller Ge content. Another bar is inserted into the hole. The compound bar is drawn at high temp to form a circular solid parent material, which is drawn to wire, thus forming the aimed fiber. |
