Closed-Loop Lane Synchronization for Optical Modulation Skew
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Solution Overview
Problem
Timing differences, or skew, between lanes in multi-lane coherent transceivers due to varying signal trace lengths and analog characteristics degrade performance and can lead to catastrophic functional failure.
Innovation Solution
Implement a closed loop system with skew detectors and variable delay circuits to adjust skew between lanes, using skew adjustment components and calibration paths to synchronize optical modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple lanes are used to increase data transmission capacity, then productivity is improved, but timing skew between lanes occurs due to varying signal trace lengths and analog characteristics
Solution Approach 1:
The patent implements a closed-loop feedback system where skew detectors continuously monitor timing differences between lanes and provide feedback to variable delay circuits. This feedback mechanism allows the system to automatically adjust and compensate for timing skew, maintaining synchronization while operating multiple lanes at high speed to maximize data transmission capacity.
Solution Approach 2:
The patent dynamically changes the delay parameter of clock signals fed to each lane using variable delay circuits. By adjusting the delay parameter based on detected skew conditions, the system compensates for timing differences caused by varying trace lengths and analog characteristics, thereby maintaining synchronization across multiple lanes.
2Manufacturing precision
If variable delay circuits and skew detectors are added to adjust lane synchronization, then timing precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the skew compensation function into separate modular components: skew detectors for each lane pair and variable delay circuits for clock signal adjustment. This segmentation allows each component to perform a specific function independently, making the overall system more manageable and easier to integrate into existing multi-lane architectures despite the increased complexity.
Data Source
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AI summary
A system for transmitting signals via serial links includes a plurality of lanes for combining data onto a transmission media, a skew detector configured to detect skew among two of the plurality of lanes, and a variable delay circuit controlled by the skew detector, configured to delay the start of a clock signal to circuitry of one of the plurality of lanes.