OPTICAL FIBER SUITABLE FOR MEASUREMENT OF STRAIN WITH HIGH RESOLUTION AND METHOD FOR MEASUREMENT OF PHYSICAL QUANTITY

摘要

PROBLEM TO BE SOLVED: To enable measurement of strain with high resolution such as about several mm to several hundreds mm by using a coated optical fiber. SOLUTION: Plural kinds of fiber gratings 21 having different reflection characteristics or transmission characteristics are recorded in the coated optical fiber 1. The plural kinds of fiber gratings 21 include at least a first fiber grating which reflects or transmits light of first wavelength and a second fiber grating which reflects or transmits light of second wavelength different from the first wavelength. The second fiber grating is formed at a position apart from and along the axial direction of the position where the first fiber grating is formed.