| 摘要 |
PROBLEM TO BE SOLVED: To quickly measure characteristic distribution of an optical fiber to be measured simply by applying light from one end of the optical fiber to be measured, and to generate a Brillouin frequency shift or a BDG shift having an improved S/N ratio by removing noise.SOLUTION: With a lock-in frequency fof a modulation period 1/fof period modulation reference light as a reference, a lock-in detector 26 extracts only DC or a low-frequency component from which noise is removed from the output of a frequency analyzer 20 to detect a Brillouin frequency shift at a certain position from the DC or the low-frequency component. Thus, a need for a function of repeating complex spectrum arithmetic processing for removing noise is eliminated from among functions that an electric spectrum analyzer has, thus quickly measuring the characteristic distribution of an optical fiber FUT to be measured by that amount. The Brillouin frequency shift capable of quickly measuring the characteristic distribution of the optical fiber FUT to be measured and improving the S/N ratio by removing noise can be obtained.SELECTED DRAWING: Figure 1 |
