| 摘要 |
PROBLEM TO BE SOLVED: To eliminate an effect of a Fresnel reflection in the vicinity of a Fresnel reflection generating section, measure a Brillouin frequency shift, and reduce an error. SOLUTION: In a Brillouin frequency shift measurement method, a light receiving section 4 receives a backscatter Brillouin light generated in a fiber 3 to be measured, and the Brillouin frequency shift is measured in the vicinity of the Fresnel reflection generating section. A light source 1 is used which has a spectral line width ofΔf for satisfyingαSL≥R×Δf<SP>2</SP>/[4×(ν<SB>B</SB>)<SP>2</SP>+Δf<SP>2</SP>], where R is a Fresnel reflection intensity ratio within the fiber 3 to be measured,αis a Brillouin scatter loss coefficient. S is a backscatter Brillouin light receiving coefficient, L is a measurement range length expressed by a distance from the vicinity of the Fresnel reflection generating section, andν<SB>B</SB>is the Brillouin frequency shift. COPYRIGHT: (C)2008,JPO&INPIT
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