| 摘要 |
<p>PURPOSE:To measure value of voltage to be measured accurately, by a method wherein an optical fiber phase modulated according to a change in the physical quantity to be measured is received, converted into an electrical signal with an electrooptic element and respective frequencies are separated with an electrical signal processing section to pick up the frequency component of a voltage to be measured. CONSTITUTION:Light emitted from a light source 12 is turned to a linearly polarized light with a polarizer 14, focused and propagated to a polarization maintaining optical fiber 15 with a lens 13 and made a parallel light with a lens 16 to be transmitted through an electrooptic element 17. At this point, this linearly polarized light is subjected to a phase modulation by a voltage V to be measured to be changed to an elliptically polarized light which is focused and propagated with a lens 18 to a polarization maintaining optical fiber 19 to be transmitted through a polarization beam splitter 21. With such an arrangement, intensity of the light become proportional to the voltage being measured and light is focused with a light receiving element 22 and converted to an electrical signal with an electrical signal processing section 23. Then, after conversion to the electrical signal respective frequencies are separated with an electrical signal processing section 23 to extract only the frequency component of the voltage to be measured thereby detecting a correct value of the voltage being measured.</p> |
