Patent ID: 7483459
Filing Date: 2009-01-27
Classification: H01S

Abstract:
1. A laser driver for driving a semiconductor laser diode, comprising: a pair of transistors operated in a differential mode, each transistor having an output, one of outputs being coupled with an anode of the laser diode and the other output of the paired transistor being coupled with a cathode of the laser diode; and a pair of load circuits each connected between the output of the paired transistor and a power supply line, each load circuit including a resistor and a switch connected in series to the resistor, the resistor terminating each output of the paired transistor when the switch is turned on, wherein the switch in respective load circuits isolates the output of the paired transistor from the power supply line by being turned off when the output of the paired transistor is directly coupled with the laser diode, and the switch in respective load circuits connects the output of the paired transistor to the power supply line by being turned on when the output of the paired transistor is indirectly coupled with the laser diode via a capacitor, and wherein an on-resistance of the switch in respective load circuits is controlled depending on a temperature of the laser diode.