Circuit for driving a laser diode which has a feed-forward type APC circuit and method for driving a laser diode by using the APC circuit

摘要

In a circuit for a driving laser diode which has a feed-forward type APC circuit, the average value of an input signal A is detected by an average value detector, and the value corresponding to the mark rate thereof is input to a memory control circuit. The memory control circuit is connected to plural memories (memory A, memory B, memory C). Each of the memories stores data having different characteristics according to the temperature with respect to the value corresponding to pulse driving current Iac of a laser diode and the value corresponding to bias driving current Idc of the laser diode. The memory control circuit selects a memory to be used according to the mark rate detected, reads out the value corresponding to the pulse driving current Iac and the value corresponding to the bias current Idc according to the temperature from a temperature sensor, and determines the pulse driving current Iac and the bias current Idc.