Circuit and method for measuring and correcting signal offset at two points

A silicon photonic receiver circuit, comprising:

• a single-ended amplifier stage;
• a photodiode configured to feed a signal to the single-ended amplifier stage;
• a differential amplifier stage receiving input from the single-ended amplifier stage;
• a controller configured to measure and modify at least one operational parameter of the signal, the controller including:
• a first controller input, and
• a second controller input;
• a first offset polarity detector-low pass filter (OPD-LPF) circuit connecting an output of the differential amplifier stage to the controller through the first controller input;
• and
• a second OPD-LPF circuit connecting the differential amplifier stage to the controller through the second controller input;
• wherein the controller measures the at least one operational parameter of the signal for offset based on input from the first OPD-LPF circuit and the second OPD-LPF circuit, and wherein the controller modifies the at least one operational parameter of the signal to correct signal offset.

A method for correcting offset in a signal, the method comprising:

• calibrating a signal carried by a circuit by:
• measuring at least one operational parameter of the signal with a controller, the controller configured to measure the at least one operational parameter of the signal through a first offset polarity detector-low pass filter (OPD-LPF) circuit connecting the controller to the circuit, and
• calibrating the signal with the controller by modifying the at least one operational parameter of the signal at an input of the circuit in a first feedback loop;
• and
• tracking the signal by:
• measuring the at least one operational parameter of the signal at an output of the circuit, the controller measuring the signal through a second OPD-LPF circuit.