Polarity Independent Laser Monitor Diode Current Sensing Circuit For Optical Modules

摘要

A laser bias control and monitoring circuit receives a monitor diode current on an input node and generate a bias current for a laser diode on an output node where the monitor diode current flows into (positive polarity) or out of (negative polarity) the input node. The laser bias control and monitoring circuit includes a polarity independent current sensing circuit configured to receive the monitor diode current in either positive or negative polarity and to generate a normalized output current having a magnitude proportional to a magnitude of the monitor diode current. In this manner, the laser bias control and monitoring circuit can be used with laser diode and monitor diode combination in either the common anode or the common cathode configuration, or with the monitor diode current being provided from the anode or cathode of the monitor diode. No reprogramming or reconfiguration of the circuit is required.