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US 12,470,296 B2Granted
System and method for reducing polarization dependent loss in an optical link
AssigneeHuawei Technologies Co., Ltd.
InventorsZhiping Jiang, Xiang Lin
Life of this patent
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Abstract
The disclosed systems and methods are for reducing polarization dependent loss in an optical link including: i) changing, by a state of polarization (SOP) controller, an SOP of an optical signal propagating in the optical link; ii) computing, by a link controller, a polarization dependent loss (PDL) in a portion of the optical link; iii) generating, by the link controller, a control signal according to the PDL; and iv) based on the control signal, changing, by the SOP controller, the SOP of the optical signal.
Claims13
A system for reducing polarization dependent loss (PDL) in an optical link comprising:
- a state of polarization (SOP) controller configured to change an SOP of an optical signal propagating in the optical link;
- a link controller operatively connected to the SOP controller;
- a first pilot tone detector (PTD) configured to determine a first power difference ΔP1 of a first set of amplitude modulation pilot tone (PT) signals, the first set of amplitude modulation PT signals being embedded in X-polarization and Y-polarization components of the optical signal before the optical signal is propagated through a first optical element included in the optical link, the first PTD being configured to provide the first power difference of the first set of amplitude modulation PT signals to the link controller;
- and
- a second PTD configured to determine a second power difference ΔP2 of a second set of amplitude modulation PT signals in the optical signal, the second set of amplitude PT signals being sensed after the optical signal is propagated through the first optical element, the SOP controller, and a second optical element included in the optical link, the second PTD being configured to provide the second power difference of the second set of detected PT signals to the link controller, the second set of PT signals having been affected by the PDL due to the first optical element and the second optical element,
- the link controller being configured to:
- control the SOP controller to change polarization of signals propagating therethrough;
- compute the PDL based on the power difference ΔP1 of the first set of detected PT signals and the power difference ΔP2 of the second set of detected PT signals;
- and
- iteratively:
- control the SOP controller to expose the optical signal to different polarization states, and
- compute the PDL,
- until the determined PDL is less than or equal to an acceptable threshold.
10 more elements
A method for reducing polarization dependent loss (PDL) in an optical link, the method being executed by a link controller, the method comprising:
- changing, by a state of polarization (SOP) controller operatively connected to the link controller, an SOP of an optical signal propagating in the optical link;
- determining, by a first pilot tone detector (PTD) communicatively connected to the link controller, a first power difference ΔP1 of a first set of amplitude modulation pilot tone (PT) signals, the first set of amplitude modulation PT signals being embedded in X-polarization and Y-polarization components of the optical signal before the optical signal is propagated through a first optical element included in the optical link;
- providing, by the first PTD, the first power difference ΔP1 to the link controller;
- determining, by a second PTD communicatively connected to the link controller, a second power difference ΔP2 of a second set of amplitude modulation PT signals in the optical signal, the second set of amplitude modulation PT signals being sensed after the optical signal is propagated through the first optical element, the SOP controller, and a second optical element included in the optical link;
- providing, by the second PTD, the second power difference ΔP2 to the link controller;
- computing, by the link controller, a polarization dependent loss (PDL) based on the first power difference ΔP1 and the second power difference ΔP2;
- changing, by the SOP controller, the SOP of the optical signal;
- and
- iteratively:
- controlling the SOP controller to expose the optical signal to different polarization states, and
- computing the PDL,
- until the determined PDL is less than or equal to an acceptable threshold.
9 more elements
Dependencies are inferred from the claim text.