OPTICAL FIBER STRAIN MEASURING DEVICE

To avoid the occurrence of MI and improve reception sensitivity.SOLUTION: The present invention is constituted by comprising: a light source unit for outputting an optical pulse train obtained by combining optical pulses of mutually different first to n-th wavelengths (n=integer 2 or greater) after adding mutually different delays to each of these; a wavelength control unit for separating backward Brillouin scattered light occurring in an optical fiber that is the object of measurement by probe light into the first to N-th wavelengths and thereafter adding mutually different delays to backward Brillouin scattered light of the m-th wavelength (m=1 to n-1, inclusive), then combining these; and a detection unit for detecting the light outputted from the wavelength control unit and outputting it as a phase difference signal. For each wavelength, the sums of delay amounts added by the light source unit and the wavelength control unit are mutually equal.SELECTED DRAWING: Figure 1 【課題】ＭＩの発生を回避し、受信感度を改善させる。【解決手段】互いに波長が異なる第１〜第ｎ（ｎは２以上の整数）の波長の光パルスそれぞれに、互いに異なる遅延を与えて合波して得られる光パルス列をプローブ光として出力する光源部と、プローブ光により測定対象となる光ファイバで発生する後方ブリルアン散乱光を第１〜第Ｎの波長に波長分離した後、第ｍ（ｍは１以上ｎ−１以下の整数）の波長の後方ブリルアン散乱光に、互いに異なる遅延を与えて合波する波長制御部と、波長制御部から出力された光を検波して位相差信号として出力する、検波部とを備えて構成される。各波長について、光源部と、波長制御部とで与えられる遅延量の和が、互いに等しい。【選択図】図１