| 摘要 |
PURPOSE:To satisfactorily follow the rapid transition state of input signals thereby enabling the high quality output photo-signals to be transmitted by a method wherein a resistor is interposed between the collector of a transistor wherein the driving current is running to a laser diode and the laser diode itself. CONSTITUTION:A resistor R1 is interposed between the cathode of a laser diode LED and the collector of a transistor TrQ1. Next, when the driving current running in the TrQ1 starts to be raised, the voltage between both ends of the resistor is boosted while the voltage between collector and emitter of the TrQ1 is lowered as the TrQ1 almost reaches the saturated state, the frequency characteristics are to be deteriorated. Resultantly, the driving current is to be raised slowly. On the other hand when TrQ1 reaches the non-conductive state the driving current running to the LED is cut off. At this time, the TrQ4 reaches the conductive state thereby rapidly decreasing the potential difference between both ends of the resistor R1 for making the driving current fall down steeply. Through these procedures, the driving current compensating the characteristics of the LED can be generated thereby enabling the limit of the rapid modulation to be raised. |
