| 摘要 |
PURPOSE:To perform high-precision detection in AC signal form even when a rotating speed is low by splitting light from a laser into two linear polarized light beams through a polarization beam splitter and propagating them through a single-mode optical fiber loop 3, and monitoring the peak value and obtaining an output voltage. CONSTITUTION:The light from the laser 1 is split by the polarization beam splitter 9 into two linear polarized light beams which have mutually orthogonal planes of oscillation, which are entered into the optical fiber loop 3 through lenses 4a and 4b. The light beams projected from both projection terminals have a phase shift DELTAtheta proportional to the rotating speed owing to Sagnac effect. The two mutually-orthogonal linear polarized light beams passed through the polarization beam splitter 9 are put together into elliptic polarized light, which is passed through a phase modulator 7 to apply a phase bias asinomegat; and it is converted into light intensity by an analyzer 8. It is converted into an electric signal by a photodetector 5, whose output is monitored by a peak detecting circuit 12 to obtain a DC voltage proportional to the phase difference DELTAtheta. |
