| 摘要 |
PROBLEM TO BE SOLVED: To suppress the jitter by measuring the off-time of a driving signal to output a time signal at a corresponding level, and controlling the driving current according to a control signal corresponding to the time signal so as to more delay the rise of the driving current with a shorter measured off-time. SOLUTION: A time measuring part 11 is provided for measuring the time lapsed from the time at which a driving current is cut off. A current controller 12 is provided for controlling the rise of the next driving current for a shorter time measured by the measuring part 11, so that the time taken from the inversion of a driving signal VIN to the logic level H until the driving current If actually exceeds a light emission start current value is longer in the decreasing order of the off-time. This allows the light emission timing of a laser diode LD to be const. to the rising timing of the driving signal VIN. When data are transmitted according to the blinking of the laser diode LD, the jitter can be suppressed. |
