| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a process for a heat treatment for discharging hydrogen to the outside after a high-pressure hydrogen process by removing part of a carbon layer from a carbon-coated fiber formed by coating a bare fiber with a carbon layer and forming a grating on the core of the exposed bare fiber. SOLUTION: The carbon-coated fiber formed by coating the surface of the bare fiber 1 with the fine carbon layer 2 is used and the optical fiber 1 having the carbon layer 2 removed within a specific range is put in a specific processing chamber and treated with hydrogen in a high-pressure hydrogen atmosphere. The specific part which has the carbon layer 2 removed is irradiated by an excimer laser to vary the refractive index, thereby forming a grating 1c. Therefore, hydrogen penetrates only the part of the bar fiber 1a which has the grating 1c formed by removing the carbon layer 2 and the part impregnated with the hydrogen can be made extremely small, so the process for the heat treatment can nearly be eliminated. |
