| 摘要 |
PURPOSE:To keep laser-beam detecting outputs to an automatic power control circuit at an approximately the same level by mounting two or more of light-receiving sections to a light-receiving means and selectively changing over these light-receiving sections in response to the changeover of laser-beam output values. CONSTITUTION:Elements such as a semiconductor laser element 2 and a photodiode chip 3 are each fitted and fixed to a base 1 for a laser device. Secondary laser beams are outputted even from a rear surface in the element 2 at that time, and received by the chip 3 for monitor, and the output level of laser beams is detected. A high-sensitivity region 31 and a low-sensitivity region 32 are formed adjacently on the same chip 3 at that time. Beam detecting outputs from such several region 31, 32 are changed over and selected in response to the changeover of output modes for laser beams, and transmitted over an automatic power control circuit. The region 31 is selected on a low output mode and the region 32 on a high output mode respectively at that time. Accordingly, laser- beam detecting outputs to the automatic power control circuit can be brought to an approximately the same level. |
