| 摘要 |
PURPOSE:To obtain favorable light output waveforms over the whole region of an environmental temp. range by adjusting the attenuation amount of attenuation means based on a temp. detected by a semiconductor laser element. CONSTITUTION:The temperature of a semiconductor laser element 1 is detected by a temp. detection circuit 5 and a detected temperature is given to a light attenuation control circuit 6. The light attenuation control circuit 6 controls the attenuation amount of a light attenuation circuit 2 based on the detected temperature. In other words, the light attenuation control circuit 6 gives the light attenuation amount corresponding to temp. dependence of oscillation characteristics of the semiconductor laser element 1 to the light attenuation circuit 2. The value of a ratio (Ib/Ith) between bias current and oscillation threshold current values does not have temp. dependence and no light output waveforms fluctuate even if the environmental temperature of a semiconductor laser varies. |
