| 摘要 |
PURPOSE:To inhibit a mode-hop generated by the change of an ambient temperature and applied currents by mounting a circuit generating a triangular current waveform for making sure the stability of a semiconductor laser, a circuit making the triangular current waveform interrupt after the division of a signal and a circuit confirming the stability of the semiconductor laser. CONSTITUTION:A triangular current waveform generating circuit 2 is connected to a semiconductor laser 1 through a circuit 3 making a triangular current waveform interrupt after the division of a signal together with a printing signal generating section 5, and the triangular current waveform is made to interrupt while being timed with the division of the signal. On the other hand, a circuit 4 making sure the stability of the semiconductor laser 1 detects the presence of a desired mode in a stable region or an unstable region by detecting the point of variation of an output level from an output waveform from a photodetector 11 monitoring an output from the semiconductor laser 1. When an approach to the unstable region of the desired mode is decided, measures such as the correction etc. of currents applied to the semiconductor laser, a high-frequency overlapping parameter, an ambient temperature or the like are taken. |
