| 摘要 |
PURPOSE:To enable a stable modulation by high-speed data while keeping the quenching ratio larger by driving a semiconductor laser so that relaxation oscillation may be small and the variation of luminous spectrum may also be small. CONSTITUTION:A semiconductor laser 1 is provided with a drive circuit 2 which supplies drive current according to input data, the duty in non-luminous status or low-luminous status is set to less than 100%, drive is controlled so that a high-luminous status is retrieved within one time slot of input data from a modulation status of non-luminous status or low-luminous status. Thus, continuation time of non-luminous status or that of low-luminous status is always constant and the residual carrier of the semiconductor laser 1 is always equal to a certain large value regardless of data pattern. It allows the relaxation oscillation to be small and the fluctuation of luminous spectrum to be small and a stable modulation drive with small pattern effect to be achieved even if the bias current is set to a small value and quenching ratio to a large value. |
