| 摘要 |
PURPOSE:To prevent the lights-out of a semiconductor laser at the time of switching an output power from being generated by controlling the power of the semiconductor laser in performing recording and erasure, and simultaneously making the output signal of a first comparator coincide with that of a holding circuit corresponding to the output signal of a second comparator. CONSTITUTION:The output signal is held by the holding circuit 22 at the time of performing the recording or the erasure, and switching devices (12-14) select the output signal of the holding circuit 22, and a first current source 21 permits a current to flow on the semiconductor laser 11 corresponding to a signal selected by the switching devices. And the second comparator 31 compares the output signal of the holding circuit 22 with that of the first comparator 20, and coincidence between the output signal of the first comparator 20 and that of the holding circuit 22 can be obtained corresponding to the output signal of the second comparator 31. Furthermore, a second power source 29 controls the recording power or erasure power of the semiconductor laser 11 by permitting the current to flow on the semiconductor laser 11. In such a way, it is possible to prevent the lights-out of the semiconductor laser 11 from being generated at the time of switching the output power of the semiconductor laser 11. |
