Optical receivers with dc cancellation bias circuit and embedded offset cancellation
AssigneeElenion Technologies, LLC
InventorsAriel Leonardo Vera Villarroel, Abdelrahman Ahmed, Alexander Rylyakov
Life of this patent
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Abstract
In optical receivers, cancelling the DC component of the incoming current is a key to increasing the receiver's effectiveness, and therefore increase the channel capacity. Ideally, the receiver includes a DC cancellation circuit for removing the DC component; however, in differential receivers an offset may be created between the output voltage components caused by the various amplifiers. Accordingly, an offset cancellation circuit is required to determine the offset and to modify the DC cancellation circuit accordingly.
Claims21
1-13. (canceled)
An optical receiver circuit for receiving a differential input current signal including a first input current component and a second input current component from a photodetector in response to an optical signal;
- a trans-impedance amplifier (TIA) configured for converting the differential input current signal into a differential input voltage signal comprising a first input voltage component and a second input voltage component;
- a DC cancellation circuit (DCCC) configured for cancelling DC portions of the differential input current signal by generating a first difference between the first input current component and a first reference current signal, and a second difference between the second input current component and a second reference current signal, and configured for sinking the DC portions of the differential input current signal based on the first difference and the second difference;
- and
- an offset cancellation circuit (OCC) configured for obtaining a first voltage sample and a second voltage sample after the TIA, and for cancelling an offset between the first input voltage component and the second input voltage component based on the first voltage sample and the second voltage sample.
An optical receiver circuit for receiving a differential input current signal including a first input current component and a second input current component from a photodetector in response to an optical signal;
- a trans-impedance amplifier (TIA) configured for converting the differential input current signal into a differential input voltage signal comprising a first input voltage component and a second input voltage component;
- a DC cancellation circuit (DCCC) configured for cancelling DC portions of the differential input current signal by generating a first difference between the first input voltage component and a first reference voltage, and a second difference between the second input voltage component and a second reference voltage, and configured for sinking the DC portions of the differential input current signal based on the first difference and the second difference;
- and
- an offset cancellation circuit (OCC) configured for obtaining a first voltage sample and a second voltage sample after the TIA, and for cancelling an offset between the first input voltage component and the second input voltage component based on the first voltage sample and the second voltage sample.
Dependencies are inferred from the claim text.