CURRENT/VOLTAGE SIMULTANEOUS MEASURING APPARATUS USING OPTICAL FIBER

PURPOSE:To enable simultaneous measurement of voltage and current in the same optical system, by using light with the wavelength lambda1 and light with the wavelength lambda2 a half that lambda1 for the measurement of voltage (electric field) and current (magnetic field) respectively. CONSTITUTION:Light with the wavelength lambda1 from a light source 1a and light with the wavelength lambda2 a half that lambda1 from a light source 1b are converged with an optical multiplexer 2 to be made incident into a sensor section from an optical fiber 3a. At the sensor section, the light with the wavelength lambda1 is used for the measurement of voltage (electric field) while the light with the wavelength lambda2 for the measurement of current (magnetic field). In addition, the light with the wavelength lambda1 is turned to a circularly polarized light as a wavelength plate 6 acts as 1/4 wavelength plate while the light with the wavelength lambda2 done to a linearly polarized light as a wavelength plate 6 acts as 1/2 wavelength plate. These lights are shifted to P1 and P2 in the light level respectively passing through a polarization beam splitter 5b, wherein P1=alpha(1+sinGAMMA) (GAMMA is phase difference) while P2=alpha(1+sin2phi) (phi is angle of rotation). The lights with the light levels P1 and P2 are diverged with an optical demultiplexer 9 and then, converted to electricity respectively with light receiving elements 10a and 10b.