Patent ID: 7570680

Claim:
A laser diode driver to provide a bias current and a modulation current to a laser diode by receiving a driving signal, comprising: a plurality of switched current sources, each switched current source including a differential circuit having a pair of bipolar transistors with commonly connected emitters and a current source connected with the emitters, the current source outputting a current as a portion of the modulation current to the laser diode; a bias current source for providing a bias current to the laser diode; a photodiode to monitor a portion of an optical output from the laser diode; and an auto-power-control (APC) unit configured to constitute an APC loop combined with the laser diode, the photodiode and each current source of respective switched current sources, the APC loop for maintaining the optical output emitted from the laser diode constant, wherein each current output from each current source in respective switched current sources is different in at least one of amplitude, a phase and a pulse width.