| 摘要 |
An optical scanning apparatus comprises an optical waveguide having electro-optic effects, grating-shaped electrodes located on the optical waveguide, a driving circuit for applying a voltage across the electrodes, and a scanning device. A voltage sweep device applies a voltage, which is swept within a predetermined range, across the electrodes within a period, during which an optical wave having been radiated out of the optical waveguide is impinging upon a region outside of an effective scanning region with respect to a recording material. A photodetector detects the optical power of the radiated optical wave impinging upon the region outside of the effective scanning region. A correction device calculates an offset voltage VOFF, which corresponds to the minimum diffraction efficiency of the optical wave guided through the optical waveguide, from an output of the photodetector when the swept voltage is applied across the electrodes. Thereafter, the correction device adds the offset voltage VOFF to a drive voltage, which is applied across the electrodes by the driving circuit, during a period during which the radiated optical wave scans the effective scanning region.
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