| 摘要 |
PROBLEM TO BE SOLVED: To allow high-precision measurement of a Brillouin frequency shift by neither raising an extreme drop in signal intensity nor broadening a width of a Brillouin spectrum even in the measurement of Brillouin frequency shift distribution with increased distance resolution. SOLUTION: A first optical signal and a second optical signal are used as first light. The first optical signal comprises first pulse light (with a pulse width of T) and second pulse light (with a pulse width ofΔT), satisfies T>ΔT, and satisfies 0≤τ≤1/Δf<SB>b</SB>, whereinτis a delay time from the trailing edge of the first pulse light to the rising edge of the second pulse light. The second optical signal comprises a combination of first pulse light which is the same as that of the first optical signal and second pulse light having different amplitude or phase from the first optical signal, satisfies T>ΔT, and satisfies 0≤τ≤1/Δf<SB>b</SB>. The power of second light with respect to the first optical signal and the second optical signal is measured. The difference between the measurement result of the power of the second light with respect to the first optical signal and the measurement result of the power of the second light with respect to the second optical signal is determined. COPYRIGHT: (C)2007,JPO&INPIT
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