OPTICAL CURRENT SENSOR

PROBLEM TO BE SOLVED: To enable the accurate measurement by removing a light source noise from a detection signal output from a sensor head even if the sensor head and a light source are disposed very far from each other.SOLUTION: The optical current sensor includes a light source 10 that emits optical signals with different wavelengths (for a detection signal and for a reference signal) at the same time, a sensor head 15, a photoelectric converter 20, a first optical fiber transmission path 11 that connects between the light source and the sensor head 15, and a second optical fiber transmission path 12 that connects between the sensor head and the photoelectric converter. The first optical fiber transmission path and the second optical fiber transmission path propagate the optical signals with the different wavelengths. At appropriate positions of opposite ends of both optical fiber transmission paths, an optical splitter or an optical multiplexer is provided. Thus, the optical signal for the reference signal is propagated avoiding the sensor head and the optical signal for the detection signal is propagated to input to the sensor head. The light emitted from the light source at the same time enters the photoelectric converter at the same timing without a time difference.SELECTED DRAWING: Figure 1 【課題】 光源とセンサヘッドの設置位置が非常に離れている場合でも、センサヘッドから出力される検出信号から光源ノイズを除去し、精度の良い測定が行えること【解決手段】 異なる波長の光信号（検出信号用と参照信号用）を同時に出射する光源１０と、センサヘッド１５と、光電変換器２０と、光源とセンサヘッド１５とを接続する第一光ファイバ伝送路１１と、センサヘッドと光電変換器とを接続する第二光ファイバ伝送路１２と、を備える。第一光ファイバ伝送路と第二光ファイバ伝送路は、異なる波長の光信号を伝搬する。両光ファイバ伝送路の両端適宜位置に光分波器や光合波器を設け、参照信号用の光信号はセンサヘッドを迂回し、検出信号用の光信号がセンサヘッドに入力するようにする。同一時刻に光源から出射した光は、時間差を発生せずにそれぞれから同一タイミングで光電変換器に入射する。【選択図】 図１