| 摘要 |
<p>PURPOSE:To improve durability of an optical fiber used as temperature sensor with respect to high temperature. CONSTITUTION:Quartz optical fiber covered with a non-combustible polyimide resin is used as optical fiber 5 utilized as a temperature detection end and a waveguide. The polyimide resin covered with the quartz optical fiber sublimates if held at a high temperature and is kept from undergoing a stress to prevent the lowering of the transmissivity of light as caused by a microbending. The optical fiber 5 is covered with an acid resisting fireproof alloy to achieve higher durability with respect to a high temperature, which can prevent the roughing of the surface of a metal pipe 6 as caused when the optical fiber is held at a high temperature for a long time. In addition, as the surface of the metal pipe 6 will not rough when held at a high temperature, fusing or fastening will not occur between the optical fiber 5 and the metal pipe 6. This enables the prevention of disconnection of the optical fiber owing to a difference in the coefficient of thermal expansion between the optical fiber 5 and the metal pipe 6.</p> |
