| 摘要 |
PURPOSE:To provide an optical magnetic field measurement apparatus with high measurement precision even when an environmental temperature changes by subtracting a DC voltage proportional to the temperature of a light source from a DC component of an output voltage of a photo-detector when an AC component of the output voltage of the photo-detector is divided electrically by the DC component. CONSTITUTION:An optical magnetic field measurement apparatus for measuring alternative current magnetic field consists of a light source 1, a magneto-optic material 5 a photo-detector 9, and a signal processor 10, in which the Faraday effect is used and the measurement is carried out through dividing electrically an AC component of an output voltage of the photo-detector by a DC component. The characteristics are presented as a DC voltage proportional to the temperature of the light source 1 is subtracted from the DC component of the photo-detector output voltage. When temperature of the light source 1 changes, the emitted peak wavelength changes and the AC component of the photo-detector output voltage changes, however, by using this optical magnetic field measurement apparatus, the DC component of the output voltage of the photo-detector 9 changes in the same way as that of the AC component according to the DC voltage proportional to the temperature variation of the light source 1 therefore, the output after dividing operation by the signal processor 10 can be maintained constant. |
