| 摘要 |
PURPOSE:To transmit physical quantity measurement light through one optical fiber by processing two light source beams which have different wavelengths by using a polarizer which polarizes only one wavelength light beam and an analyzer. CONSTITUTION:Light beams with wavelength lambda1 and lambda2 from light sources 20a and 20b are incident on a Faraday element 5 through a multiplexer 21, one optical fiber 22, etc., and beam splitter 24 as a polarizer which polarizes only the light with the wavelength lambda1 as specified, and only the light with the wavelength lambda1 has its plane of polarization rotated in proportion to the intensity of a magnetic field applied to the element 5. Then, light intensity modulation is imposed on the light with the wavelength lambda1 in proportion to the intensity of the applied magnetic field through a beam splitter 26 as a polarizer which polarizes only the light with the wavelength lambda1 to obtain light which is not modulated, so that the light is passed through one optical fiber 29 and demultiplexed by a demultiplexer 30. The polarized modulated light and unmodulated light are photodetected by optical receivers 31 and 32 respectively and their photodetection outputs are processed by a divider 35 to measure the intensity of the applied magnetic field. Consequently, physical quantity measurement light is transmitted through one optical fiber and a measurement error due to the characteristic error of the optical fiber is eliminated. |
