A driver circuit for a semiconductor laser of the invention comprises:
first bias current supply means for supplying, at least at a time of
non-output of data, a first bias current to an LD; signal processing
means for generating a pulse current control signal in which a burst data
signal is delayed, and generating a second bias current control signal
which rises more rapidly by a predetermined time than the rise of burst
data included in the pulse current control signal; pulse current supply
means for supplying to the LD a pulse current generated in accordance
with the pulse current control signal; and second bias current supply
means for supplying to the LD a second bias current generated in
accordance with the second bias current control signal.