摘要 |
<p>A process is disclosed for making an optical fiber having a graded index glass core enveloped by a cladding material. The ingredients from which the peripheral part of the core glass is to be formed are placed in a closed tube of the cladding material which is more refractory than the core glass. The ingredients are melted to form a glassy liquid which is fined within the tube and then coated (for example, by rotational casting) on the inner surface of the tube. Additional ingredients, from which the inner part of the core glass is to be formed, are then placed in the coated tube, melted and similarly coated on the inner surface of the tube. In this way successive core glass layers, each having a different index of refraction, may be formed within the tube of cladding material. The temperature is then elevated further and the tube and glassy liquid drawn into a fiber.</p> |