Patent ID: 8320420
Filing Date: 2012-11-27
Classification: H01S

Abstract:
1. A laser bias control and monitoring circuit configured to receive a monitor diode current on an input node indicative of the average optical output power of a laser diode and generate a bias current for the laser diode on an output node, the monitor diode current flowing into (positive polarity) or out of (negative polarity) the input node, the laser bias control and monitoring circuit comprising: a polarity independent current sensing circuit configured to receive the monitor diode current in either the positive or negative polarity and to generate a normalized output current having a magnitude proportional to a magnitude of the monitor diode current; a first load circuit configured to convert the normalized output current into a monitor voltage signal; a second load circuit configured to convert a bias set current signal into a bias set voltage signal, the bias set current signal being indicative of a desired value of the bias current generated to bias the laser diode; a comparator configured to compare the monitor voltage signal with the bias set voltage signal, the comparator providing an error signal indicative of a difference between the monitor voltage signal and the bias set voltage signal; and an amplifier configured to receive the error signal and a reference signal and to generate a bias adjust signal for adjusting the bias current for the laser diode.