| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a fiber grating(FG) sensor which can measure a tension of a wide range by setting a grating pitch of a fiber grating to a chirped pitch. SOLUTION: The FG sensor uses a fiber grating having a chirped grating part 4B formed with a chirped pitch. In the chirped pitch, a grating pitch changes in a longitudinal direction of a bare optical fiber 1. For example, the chirped grating part 4B has the grating pitch short at the center and longer towards both end parts in the longitudinal direction of the bare optical fiber 1. While a length, the grating pitch and a chirp ratio of the chirped grating part 4B are adjusted in accordance with a wavelength band of an inputted light, e.g. the chirp ratio (a change ratio of the grating pitch of the chirped grating part 4B) is set to not smaller than 0.05 mm/mm.</p> |
