| 摘要 |
PURPOSE:To get a transmitter wherein the optical output peak value and the extinction ratio pulse width in optical waveform do not change, even if the electric-light conversion efficiency of a laser diode fluctuates. CONSTITUTION:The property that the light pulse width becomes narrower than the modulated current pulse width when a laser diode 3 is modulated with a bias lower than the threshold is made use of. This transmitter is provided with a nonconformity detecting circuit 14 which detects the decrease of light pulse width. It is further provided with a current control circuit 16 which controls the increase and decrease of a bias current at the time when this circuit detects the nonconformity. This circuit operates, belonging to a demodulated current control circuit 15 for controlling the optical output peak value to be constant. |
