| 摘要 |
PURPOSE:To obtain a heat resisting optical fiber by inserting a glass fiber strand consisting of a core and a clad into a metal tube with a gap and excess length. CONSTITUTION:The glass fiber strand 3 is coated with a heat resisting material such as metal, ceramics, carbon or thermet and the coated strad 3 is inserted into the metal tube 1 consisting of a required material. Although the outer diameter and thickness of the metal tube 1 is determined in consideration of the outer diameter, extension or the like of an optical fiber cord, the inner diameter of the tube 1 is >= the outer diameter of the optical fiber by 0.1mm or more. The excess length is determined by a difference in the coefficient of thermal expansion or elastic coefficient between the metal tube 1 and the optical fiber and the using condition of the optical fiber. At the time of inserting the strand, the surface of the strand is prevented from generating a flaw by using solid lubricant 7 such as carbon and talc or the proper quantity of lubricant to easily insert the strand. Since the optical fiber strand 3 is not coated with nylon or the like in said constitution, the strand 3 can be prevented from being deteriorated due to the dicomposition or combustion of the coating material at a high temperature and the tube 1 can be prevented from being broken by generated gas. |
