| 摘要 |
PURPOSE:To obtain an optical transmitter whereby the output of a laser diode perfectly becomes zero at the time of interrupting an optical output. CONSTITUTION:Two comparators 15 and are set so as to execute an operation at a certain level and made to be an on-state at the time of interrupting light. The respective comparators 15 and 17 becomes the on-state at the time of interrupting the optical output, control current supplied from a modulation current control circuit is made to be zero by the output of the one comparator 17 so as not to permit modulation current to flow and a transistor 14 where bias current is being permitted to flow is made to be OFF by the other comparator 15 so as to cut bias current. Thus, current permitted to flow in the laser diode 8 is forcibly made to be zero so that the optical output perfectly becomes zero. |
