| 摘要 |
PROBLEM TO BE SOLVED: To correct a transmission loss even if a change in the transmission loss caused by a difference of wavelengths of an optical fiber occurs, and to calibrate temperature distribution.SOLUTION: For instance, a first optical pulse (1,100 nm) is oscillated from an LD drive selection circuit (semiconductor laser drive selection circuit) 3, and a second optical pulse (1,050 nm) of the same wavelength as the first anti-stokes light of a back scatter generated from the first optical pulse is oscillated from a semiconductor laser (LD (3))5 for measuring an anti-stokes light wavelength loss while a third optical pulse (1,150 nm) of the same wavelength as the first stoke light of the back scatter generated from the first optical pulse is oscillated from a semiconductor laser (LD (2))4 for measuring a stokes light wavelength loss. By a signal control processing part, the transmission loss of the first anti-stokes light is corrected by the transmission loss of the second optical pulse, and the transmission loss of the first stokes light is corrected by the transmission loss of the third optical pulse. |
