US Patent 11280674 Differential trans-impedance amplifier receiver using counter-offset circuitry

A system for converting an optical signal into an electrical signal includes at least one differential Trans-Impedance Amplifier (TIA). To minimize (preferably eliminate) DC offset issues at the TIA output, an Input Counter-Offset (ICO) circuit is provided to remove the DC component of the initial optical signal from the input to the TIA. To further maximize the removal of DC offset at the TIA output, an Output Counter-Offset circuit is provided to take DC offset from the TIA output for use as a negative feedback directly to the input of the TIA. Modifications of the present invention are also intended for use with two TIA terminations and with a travelling wave photodiode.