| 摘要 |
PROBLEM TO BE SOLVED: To avoid causing a distortion in data, by a method wherein, when a continuous period of time of a logical level in which it is unnecessary to emit light from a semiconductor laser of the input data is over a predetermined period of time, a current source is stopped. SOLUTION: When a period of time of a logical level L in which it is unnecessary to emit light from a semiconductor laser 44 in data to be inputted is continuously two bits or more, a current source 43 is stopped for a predetermined time. Accordingly, it is needless to say that the current source is stopped in the period during which no data generated in a burst manner, and also the current source can be stopped for a predetermined period even in the period during which the logical level becomes L in two bits or more in the data generated in a burst manner. Therefore, it is possible to reduce a consumption power of a semiconductor laser drive circuit. Moreover, as generation of a control signal in a control signal generation part 2 and generation of a delay time in a delay adjustment part 3 are achieved by the same clock source, it is possible to hold the appropriate relationship between the data supplied to a current switching drive circuit 4 and a phase of the control signal. |
