| 摘要 |
PROBLEM TO BE SOLVED: To provide an in-metal tube optical fiber coil type vibration sensor which can be used under a high-temperature condition, has a sufficient environment resistance and enables a coil having a small diameter to be made up. SOLUTION: A heatproof optical fiber (3) is made up by forming a metal film (2) on the outer circumferential surface of an optical fiber (1) composed of a core (1a) and a cladding (1d), and then inserted into a metal tube (5) and filled up with a filling material (7), and then wound in the form of a spiral coil and sealed at its ends (5a, 5b) by a sealing material (6). Since the heatproof optical fiber (3) which is employed in the sensor, has the metal film (2) formed on its outer circumferential surface, and is inserted into the metal tube (5), the sensor is made excellent in heat resistance and can be used under the high-temperature condition. Furthermore, since the heatproof optical fiber (3) is not exposed outside, the metal film (2) is not oxidized even under a high-temperature oxidizing gas atmosphere, and the sufficient environment resistance is realized. Any tension is hardly applied to the heatproof optical fiber (3) when bending the sensor, thereby enabling the coil having the small diameter to be made up. COPYRIGHT: (C)2007,JPO&INPIT
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