| 摘要 |
PURPOSE:To enhance the transmission quality by minimizing the ripple by a method wherein the bias current value larger than the threshold value current of a semiconductor laser is constantly impressed so that the bias current may be pulse-driven as the minimum current value. CONSTITUTION:The output from a pulse generating circuit 16 is inputted to the base of a transistor 17 to turn a collector current on/off. The pulse duty ratio in the collector current value is fluctuated corresponding to the electric signals. On the other hand, a constant current is fed to a resistor 19 while in the exciting semiconductor 12, the collector current of the transistor 17 is convoluted with the current running in the resistor 19. At this time, the resistance value of the resistor 19 is set up so that the convoluted DC current may be the specified value of the amplified light intensity of the title optical fiber amplifier as well as larger than the threshold value of said exciting semiconductor laser 12. Through these procedures, within the light amplification by pulse driving, the transmission quality can be enhanced by minimizing the ripple. |
