PURPOSE: To provide optical direct current transformer which can measure a direct current with good accuracy even when the amount of light is fluctuated in a light source, a sensor part or a photo signal transmission path.
CONSTITUTION: Two light waves of different wavelengths generated in light sources 1, 2 are synthesized by a photosynthesizer 3, and transmitted by the use of the same optical path through a polarizer 5, a magnetic field sensor 6 and an analyzer 7. The P-polarized component and S-polarized component separated in the analyzer 7 are processed in a signal processing circuit 10. The light wave in this case is a light wave including an alternating current component of a constant amplitude and changing the intensity thereof. The polarizer 5 is arranged not to polarize the light wave of the second wavelength linearly, so that true direct current component and the alternating current component of the light wave are not subjected to the Faraday rotation. Even when the amount of light is fluctuated in light sources 1, 2, sensor parts 5, 6, '7, and optical transmission paths 4, 8, 9, the direct current can be measured with good accuracy with using the above amount of light as a reference.
HIGAKI MASARU
TAKAHASHI GENJI
MORI ETSUNORI
NISHIMURA MASAFUMI
KUZUSAKA SATOSHI
SHIMIZU MAKOTO
NAKAGAWA HIROTO
KANSAI ELECTRIC POWER CO