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US 10,498,461 B1Granted
Optical receivers with dc cancellation bias circuit and embedded offset cancellation
AssigneeElenion Technologies, LLC
InventorsAriel Leonardo Vera Villarroel, Abdelrahman Ahmed, Alexander Rylyakov
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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.
Claims12
An optical receiver comprising:
- at least one photodetector capable of generating a differential input current including first and second input current components in response to an optical signal;
- a trans-impedance amplifier (TIA) capable of converting the first and second input current components into first and second input voltage components;
- a DC cancellation circuit (DCCC) for cancelling a DC portion of the first and second input current components or the first and second input voltage components by comparing the first and second input current components or the first and second input voltage components to respective first and second reference voltages or currents, and sinking the DC portion of the first and second input current components based on the comparisons;
- and
- an offset cancellation circuit (OCC) capable of obtaining first and second voltage samples after the TIA and of cancelling offset between the first and second input voltage components by modifying at least one of the first or second reference voltages.
2 more elements
Dependencies are inferred from the claim text.