Sample timing control in an optical receiver
AssigneeCiena Corporation
InventorsHan Sun, Chandra Bontu, Kim B. Roberts, John Sitch, John Wolczanski
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Abstract
A method of compensating phase error between parallel digital signals of a received optical signal, in a coherent optical receiver. A phase differential between the digital signals is determined. A digital skew is imposed between the digital signals, an amount of skew imposed being an integer number of sample periods calculated to most nearly compensate the phase differential. The skewed digital signals are then digitally processed, in the frequency domain, to compensate a residual portion of the phase differential.
Claims7
In an optical receiver, a method of compensating sample phase error between parallel multi-bit-digital signals of a received optical signal, the method comprising steps of:
- identifying a first digital signal having a greatest amount of propagation delay;
- determining a respective sample phase differential between the first digital signal and a second digital signal;
- imposing a digital skew between the digital signals, an amount of skew imposed being an integer number of sample periods calculated to most nearly compensate the sample phase differential;
- and
- digitally processing the skewed digital signals, in the frequency domain, to compensate a residual portion of the sample phase differential.
Dependencies are inferred from the claim text.