| 摘要 |
PURPOSE:To improve the measurement accuracy by providing the first and the second magnetooptical substance for making the light of a light source of a linearly polarized light transmit through successively, an analyzer, a saw tooth magnetic field generator, and a phase detector, and making a magnetic field to be measured work on the second magnetooptical substance. CONSTITUTION:A linearly polarized light emitted from a light source 1 is constituted so that the plane of polarization is rotated by pi radian, by the peak value of a saw tooth magnetic field. In this state, the light emitted from the first Faraday rotator 6 passes through the second Faraday rotator 7 on which the magnetic field to be measured H is working, and an analyzer 8, only the light of a main axis direction component of the analyzer 8 is made incident on an electric signal, and this electric signal is inputted to a phase detector 10. To the phase detector 10, the driving signal of the saw tooth magnetic field generator 11 is also inputted, the phase difference of the detecting signal and the driving signal is detected, and an output being proportional to the magnetic field to be measured is obtained. In this way, the magnetic field measuring instrument having the high accuracy, which is not influenced by the characteristic drift on an optical transmission line and a photoelectric converter is obtained.
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