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US 12,476,711 B2Granted
In-phase (I) / quadrature (Q) correlation dither for modulator quadrature control
AssigneeCiena Corporation
InventorsShahab Oveis Gharan, Yves Beaulieu, Douglas McGhan, Kim Byron Roberts
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Abstract
Aspects of the subject disclosure may include, for example, obtaining two inputs xI and xQ based on a digital input signal, and causing a modulator to create two substantially orthogonal output dimensions I and Q based on the two inputs xI and xQ, by performing controlled introduction of a correlation between the two inputs xI and xQ for the modulator, and detecting a resulting output power of the modulator to facilitate operation of the modulator. Other embodiments are disclosed.
Claims21
A device, comprising:
- a modulator configured to output an optical signal;
- and
- a control system configured to cause the modulator to create two orthogonal output dimensions, in-phase (I) and quadrature (Q), based on two inputs xI and xQ derived from a digital input signal, by:
- performing controlled introduction of a correlation between the two inputs xI and xQ for the modulator, wherein the controlled introduction corresponds to use of a controlled correlated term from the input xI to the input xQ, or from the input xQ to the input xI, that is filtered out via a digital filter, and wherein the controlled correlated term enables detection of any frequency-dependent non-orthogonality within dimension I radio frequency (RF) drive signals and within dimension Q RF drive signals or within I and Q arms of the modulator;
- and
- detecting a resulting output power of the modulator to facilitate operation of the modulator.
3 more elements
A device, comprising:
- a modulator configured to output an optical signal;
- and
- a control system configured to cause the modulator to create two orthogonal output dimensions, in-phase (I) and quadrature (Q), based on two inputs xI and xQ derived from a digital input signal, by:
- performing controlled introduction of a correlation between the two inputs xI and xQ for the modulator;
- and
- detecting a resulting output power of the modulator to facilitate operation of the modulator, wherein the detecting is performed using a detection circuit comprising a photodiode, and wherein the detection circuit has a bandwidth that is less than 0.001 of a bandwidth of the input xI.
3 more elements
A device, comprising:
- a modulator configured to output an optical signal;
- and
- a control system configured to cause the modulator to create two orthogonal output dimensions, in-phase (I) and quadrature (Q), based on two inputs xI and xQ derived from a digital input signal, by:
- performing controlled introduction of a correlation between the two inputs xI and xQ for the modulator, wherein the two orthogonal output dimensions I and Q comprise dimensions XI and XQ for an X polarization;
- performing a second controlled introduction of a second correlation between two inputs yI and yQ, thereby creating two orthogonal output dimensions YI and YQ for a Y polarization based on the two inputs yI and yQ, wherein the output dimension YI is orthogonal to the output dimensions XI and XQ, and wherein the controlled introduction of the correlation between the two inputs xI and xQ and the second controlled introduction of the second correlation between the two inputs yI and yQ are performed simultaneously;
- and
- detecting a resulting output power of the modulator to facilitate operation of the modulator.
4 more elements
A device, comprising:
- a modulator configured to output an optical signal;
- a control system configured to cause the modulator to create two orthogonal output dimensions, in-phase (I) and quadrature (Q), based on two inputs xI and xQ derived from a digital input signal, by:
- performing controlled introduction of a correlation between the two inputs x and xQ for the modulator;
- and
- detecting a resulting output power of the modulator to facilitate operation of the modulator;
- and
- a transpose filter, wherein the detecting provides a measure of I/Q nonquadrature, and wherein the operation of the modulator is effected by performing digital pre-compensation of an equal and opposite amount in the transpose filter based on the measure of the I/Q nonquadrature.
4 more elements
Dependencies are inferred from the claim text.