| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for accurately measuring a cutoff wavelength of a higher mode for an optical fiber. <P>SOLUTION: A cutoff wavelength measuring method in the invention includes: (1) a first step of measuring a power spectrum P1(λ) of light output from a light source; (2) a second step of arranging a measured optical fiber 10 in such a shape (preferably spiral shape) that curvature changes in a longitudinal direction, allowing the light output from the light source to enter one end of the measured optical fiber 10, and measuring a power spectrum P2(λ) of the light output from the other end of the measured optical fiber 10; (3) a third step of obtaining a difference spectrum P(λ) that shows a difference between the power spectrum P2(λ) and the power spectrum P1(λ); and (4) a fourth step of obtaining a cutoff wavelength in a higher mode for the measured optical fiber on the basis of the difference spectrum P(λ). <P>COPYRIGHT: (C)2013,JPO&INPIT |
