Patent ID: 8457499

Claim:
A semiconductor laser drive device comprising: drive means for outputting an optical signal from a semiconductor laser by applying a bias current, or the bias current and a drive current, to the semiconductor laser based on a modulating signal; and output adjustment means for controlling a value of the bias current and a value of the drive current to apply to the drive means; wherein the output adjustment means comprises: bias current setting means for setting the bias current value, based on the drive temperature of the semiconductor laser, so that temperature characteristics of the bias current value with respect to a drive temperature are a function having a slope other than zero, wherein the bias current setting means sets the bias current value so that the temperature characteristics of the bias current value are a function including at least a first linear function that linearly changes from a lower limit temperature within a drive temperature range to a predetermined temperature within the drive temperature range, and a second linear function that linearly changes from the predetermined temperature to an upper limit temperature within the drive temperature range and that has a slope different from the first linear function, and drive current setting means for setting the drive current value, based on the drive temperature, so that temperature characteristics of the drive current value with respect to a drive temperature are a function having a slope other than zero; and wherein the temperature characteristics of the bias current value and the temperature characteristics of the drive current value are functions different from each other.