| 摘要 |
PURPOSE:To improve high-speed responsiveness of the output signal from a photodetector monitoring the output level of a semiconductor laser element. CONSTITUTION:The light beam reflected by the splitting surface 20c of a beam splitter 20 is emitted from an emitting surface 20d, passes through a square window 22 formed on an aperture component 21 as a detecting beam and is made incident on the photodetecting surface 23a of a photodetector 23 at a prescribed angle. Consequently, since the cross-sectional shape of the detecting beam is nearly the similar figure of the shape of the photodetecting surface 23a, the situation that the detecting beam is made incident on the outer peripheral portion of the photodetecting surface 23a, is prevented and the high speed responsiveness of the output signal from the photodetector 23 is improved. |
