| 摘要 |
PURPOSE:To obtain a laser emission driving device capable of controlling so that the superposition level of a high frequency signal superposed on a signal for driving laser becomes a fixed value always. CONSTITUTION:An actually superposed high frequency signal component is detected by a capacitor C3 based on a superposition signal superposing the high frequency signal from a high frequency oscillator 31 on the signal for driving laser supplied to a laser diode 11. The capacitance of a variable capacitor constituted of capacitors C1, C2 and variable capacitance diodes CD1, CD2 is varied by a DC voltage according to the signal level of the detected high frequency signal component, and the superposition level of the high frequency signal from the high frequency oscillator 31 superposed on the signal for driving laser is varied according to the capacitance of the variable capacitor. Thus, the occurrence of the difference of ability between devices due to the dispersion of the characteristics of the laser diode and the high frequency oscillator circuit is prevented. |
