Calibration for an optical communications link
AssigneeHewlett Packard Enterprise Development LP
InventorsDavid Ritter Thomas, William Lee
Life of this patent
Estimating the term…
Abstract
Examples described herein relate to calibration of an optical communications link. Data signals received over the optical communications link are measured to obtain an eye scan. A height of an upper eye region and a height of a lower eye region are compared in the eye scan. A common mode calibration value is adjusted based on any difference in the heights. A common mode adjustment circuit is then controlled based on the common mode calibration value. The common mode adjustment circuit is configured to remove a direct current bias within a receiver for the optical communications link.
Claims20
A method of calibrating a receiver for an optical communications link comprising:
- performing an eye scan by measuring data signals received over the optical communications link;
- comparing a height of an upper eye region and a height of a lower eye region;
- responsive to the height of the upper eye region being greater than the height of the lower eye region, incrementing a common mode calibration value;
- responsive to the height of the lower eye region being greater than the height of the upper eye region, decrementing the common mode calibration value;
- and
- controlling a common mode adjustment circuit based on the common mode calibration value, the common mode adjustment circuit being configured to remove a direct current bias from an output of a photodetector of the receiver.
An optical receiver comprising:
- a photodetector;
- a common mode adjustment circuit to remove a direct current bias from a current output of the photodetector;
- and
- a microcontroller comprising a processor and a memory, the memory comprising instructions that when executed by the processor cause the microcontroller to:
- obtain bit error measurements from an eye scan performed on data signals received by the optical receiver over an optical communications link;
- determine a height of an upper eye region and a height of a lower eye region from the bit error measurements;
- compare the height of the upper eye region and the height of the lower eye region;
- and
- calibrate the direct current bias that is removed by the common mode adjustment circuit based on a difference in the compared heights.
A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to:
- obtain bit error measurements from an eye scan performed on data received over an optical communications link;
- determine a height of an upper eye region and a height of a lower eye region from the bit error measurements;
- responsive to the height of the upper eye region being greater than the height of the lower eye region, increase a common mode calibration value;
- responsive to the height of the lower eye region being greater than the height of the upper eye region, decrease the common mode calibration value;
- and
- instruct an adjustment of a direct current bias that is removed from an output of a photodetector of a receiver for the optical communications link based on the common mode calibration value.
Dependencies are inferred from the claim text.