| 摘要 |
PURPOSE:To obtain a correct simultaneously regenerating signal by joining a coil with a laser in series for reproducing out of plural semiconductor lasers and selecting the time constant of an APC circuit smaller than the propagating time of heat from the laser for recording. CONSTITUTION:A semiconductor laser 1 for recording executes recording operation by a monitor 3 and a driving circuit 5. A semiconductor laser 2 for reproducing keeps an output at constant by a monitor 4, APC circuit 6 and coil 7. The heat generated from the laser 1 at the time of recording, the temperature of is propagated to the laser 2, the temperature of the laser 2 is increased and a light emitting threshold level is changed. However, by the reducing the time constant of the circuit 6 rather than the propagating time of the heat, the fluctuation in the optical output of the laser 2 is corrected and the output can be kept at constant. Since the coil 7 is joined with the laser in series 2, infiltrating in the high frequency signal of a recording current is suppressed and the correct simultaneously regenerating signal can be obtained. |
