Phase error correction in a coherent receiver
AssigneeAlcatel Lucent
InventorsNoriaki Kaneda, Andreas B. Leven
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Abstract
A method and apparatus for correcting of phase errors in a coherent optical receiver are disclosed. Embodiments include a method for calculating a phase error between in-phase and quadrature-phase component signals, multiplying the phase error by one of the component signals and subtracting the result from the other component signal to output a corrected signal.
Claims25
A method for use in a receiver for detecting and correcting phase error of a phase encoded input signal having in-phase (I) and quadrature-phase (Q) components, comprising:
- multiplying a first of the I and Q components of the phase encoded input signal and a corrected second of the I and Q components of the phase encoded input signal to provide thereby a resulting signal;
- low-pass filtering the resulting signal to produce thereby a second resulting signal;
- multiplying the second resulting signal and the first of the I and Q components of the phase encoded input signal to produce thereby a correction factor;
- and
- subtracting the correction factor from the second of the I and Q components of the phase encoded input signal to produce thereby the corrected second of the I and Q components of the phase encoded input signal.
A method for use in a receiver for detecting and correcting phase error of a phase encoded input signal having in-phase (I) and quadrature-phase (Q) components, comprising:
- processing, by an exclusive-or (XOR) operation, the sign value of a first of the I and Q components of the phase encoded input signal and the sign value a corrected second of the I and Q components of the phase encoded input signal to produce thereby a resulting signal;
- multiplying the resulting signal by a gain factor to produce thereby a second resulting signal;
- integrating the second resulting signal to produce thereby a third resulting signal;
- multiplying the first of the I and Q components of the phase encoded input signal by the third resulting signal to produce thereby a correction factor;
- and
- subtracting the correction factor from the second of the I and Q components of the phase encoded input signal to produce thereby the corrected second of the I and Q components of the phase encoded input signal.
An apparatus for detecting and correcting phase error of a phase encoded input signal having in-phase (I) and a quadrature-phase (Q) components, comprising:
- a first multiplier for multiplying a first of the I and Q components of the phase encoded input signal and a corrected second of the I and Q components of the phase encoded input signal;
- a low-pass filter for filtering the output of the first multiplier;
- a second multiplier for multiplying the output of the low-pass filter by the first of the I and Q components of the phase encoded input signal to produce thereby a correction factor;
- and
- an adder, for offsetting the second of the I and Q components of the phase encoded input signal by the correction factor.
An apparatus for detecting and correcting the phase error of a phase encoded input signal having an in-phase (I) component and a quadrature-phase (Q) component, comprising:
- an exclusive-or gate with a first of the I and Q components of the phase encoded input signal and a corrected second of the I and Q components of the phase encoded input signal as inputs;
- a first multiplier for multiplying the output of the exclusive-or gate by a gain factor;
- an integrator for integrating the output of the first multiplier;
- a second multiplier for multiplying the output of the integrator by the first of the I and Q components of the phase encoded input signal to produce a correction factor;
- and
- an adder, for offsetting the second of the I and Q components of the phase encoded input signal by the correction factor to produce the corrected second of the I and Q components of the phase encoded input signal.
A coherent receiver system comprising:
- a optical receiver with an adjustable phase control mechanism;
- means for determining and outputting a digital phase correction signal;
- and
- a digital to analog converter configured to convert the digital phase correction signal to an analog phase correction signal, wherein the analog phase correction signal controls the adjustable phase control mechanism of the optical receiver.
Dependencies are inferred from the claim text.