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US 10,855,380 B2Granted
Clock recovery circuits, systems and implementation for increased optical channel density
AssigneeCiena Corporation
InventorsSadok Aouini, Bilal Riaz, Naim Ben-Hamida, Lukas Jakober, Ahmad Abdo
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Abstract
Techniques and circuits are proposed to increase averaging in the clock recovery band based on an amount of channel overlap in receivers using excess bandwidth for clock recovery, to mitigate the impact of spectral energy leaking into an active channel of interest from an adjacent active channel and to improve the accuracy of the phase estimate of the received transmitted clock.
Claims19
A flexible grid optical receiver circuit comprising:
- a phase locked loop circuit configured to receive a received signal and to output a sampling signal based on timing of the received signal;
- and
- a clock recovery circuit configured to determine a phase difference between the received signal and the sampling signal, determine a control signal based on the phase difference, and utilize the control signal to set a clock recovery bandwidth of the phase locked loop circuit,
- wherein the clock recovery bandwidth is set to filter out adjacent channel interference, wherein the clock recovery bandwidth is set to optimize channel spacing of the received channel for a given optical signal-to-noise ratio, and wherein the clock recovery circuit is configured to estimate jitter margin from neighboring channels and to utilize the estimated jitter margin to set the optimized channel spacing.
1 more element
A flexible grid optical system comprising:
- one or more flexible grid modems;
- and
- a bandwidth utilization controller communicatively coupled to the one or more flexible grid modems and configured to
- for a given optical signal-to-noise ratio target for a new channel on one of the one or more flexible grid modems, determine a required optical signal-to-noise ratio for the new channel;
- obtain estimated jitter margin from neighboring channels associated with the one or more flexible grid modems;
- and
- translate the estimated jitter margin into channel spacing for the new channel based on the given optical signal-to-noise ratio target.
4 more elements
A flexible grid optical receiver circuit comprising:
- a phase locked loop circuit configured to receive a received signal and to output a sampling signal based on timing of the received signal;
- and
- a clock recovery circuit configured to determine a phase difference between the received signal and the sampling signal, determine a control signal based on the phase difference, and utilize the control signal to set a clock recovery bandwidth of the phase locked loop circuit,
- wherein the clock recovery bandwidth is set to filter out adjacent channel interference, wherein the clock recovery circuit is configured to adjust a reference clock associated with the received signal, and wherein the reference clock has an adjustable frequency and the control signal is employed to control a frequency of the reference clock to filter out adjacent channel interference, and wherein the adjusted reference signal is combined with a feedback signal copy of the sampling signal.
1 more element
Dependencies are inferred from the claim text.