| 摘要 |
PURPOSE:To improve current efficiency, and to determine the value of DC currents flowing through a laser diode accurately by detecting the DC voltage drop of the laser diode and applying the DC voltage to a correction circuit for driving currents. CONSTITUTION:A DC bias control terminal (c) and a correction circuit for driving currents consisting of a coil 1 and a resistor 2 are connected through a resistor 9 and a voltage follower 10. Pulse voltage inputted to input terminals (a), (b) is converted into currents by transistors TR6, 7, and applied to a laser diode 4. On the other hand, the voltage drop of the diode 4 detected by the terminal (c) is applied to the voltage follower 10 through the resistor 9, and applied to a node (d) between the resistor 2 and a capacitor 8. Consequently, DC potential difference between the node (d) and the terminal (c) is removed, and unnecessary DC currents do not flow. Accordingly, Current efficiency is improved, and DC currents flowing through the diode 4 can be grasped accurately. |
