Band-Sensitive Optical Channel Swapping in C+L Systems

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Solution Overview

Problem

Conventional optical networking systems face inefficiencies in channel swapping, particularly in multi-band systems like C+L band ASE-loaded systems, due to limitations in bundling strategies, leading to slow capacity changes and increased restoration times, as existing methods do not account for the sensitivity differences between frequency bands, resulting in SNR penalties and delays in Layer 0 restoration.

Innovation Solution

Implement band-sensitive bundling techniques that differentiate swapping methods based on the sensitivity of each frequency band, allowing for more aggressive swapping in less-sensitive bands like C-band and conservative swapping in more-sensitive bands like L-band, using WSS-controlled bundling to minimize SNR penalties and enable parallel capacity changes across bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional bundling approaches are used in C+L band systems, then channel swapping can be performed, but SNR penalties occur and restoration speed is reduced

Engineering Contradiction:
ImproveSNR performanceVSAvoidrestoration speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies different bundling strategies to different frequency bands based on their sensitivity characteristics. Specifically, C-band channels use one bundling approach while L-band channels use another, recognizing that each band has different SNR sensitivity to channel swapping operations. This local differentiation resolves the contradiction by optimizing for SNR in sensitive bands while maintaining faster swapping in less sensitive bands.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the C+L band spectrum into separate C-band and L-band groups, applying independent bundling control to each segment. This segmentation allows the system to perform channel swapping in parallel across different bands with band-specific parameters, improving overall restoration speed while maintaining SNR performance through band-optimized strategies.

Inventive Principle:
Principle #1Segmentation

2Reliability

If channel swapping is performed one channel at a time, then SNR stability is maintained, but capacity change efficiency is reduced

Engineering Contradiction:
ImproveSNR stabilityVSAvoidcapacity change efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic bundling where the bundle size and composition are adjusted based on real-time system conditions, traffic patterns, and band sensitivity. This dynamic approach allows the system to swap multiple channels simultaneously when conditions permit (improving efficiency) while maintaining SNR stability through adaptive control parameters that respond to system state changes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes key parameters such as bundle size, swapping rate, and power control settings based on the specific frequency band and system conditions. By adjusting these parameters dynamically, the system achieves both SNR stability and improved capacity change efficiency, resolving the contradiction between careful single-channel swapping and fast multi-channel swapping.

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If aggressive bundling is used to speed up restoration, then restoration time is reduced, but SNR penalties increase

Engineering Contradiction:
Improverestoration timeVSAvoidSNR quality
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent applies less aggressive bundling to L-band channels which are more SNR-sensitive, while allowing more aggressive bundling in C-band channels. This local differentiation enables faster overall restoration while protecting SNR quality in the sensitive L-band, resolving the contradiction between restoration speed and SNR quality.

Inventive Principle:
Principle #3Local quality

4Device complexity

If conventional single-band bundling strategies are applied to multi-band systems, then implementation is simple, but band sensitivity differences are not accounted for

Engineering Contradiction:
Improvecontrol complexityVSAvoidband sensitivity management
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the multi-band system into independently controllable C-band and L-band groups, each with its own bundling parameters and control logic. This segmentation manages complexity by creating modular band-specific controllers while properly accounting for sensitivity differences through dedicated parameter sets for each band.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces SNR penalties and enhances restoration speed by allowing independent operation of channel controllers in each band, reducing the impact of changes in one band on the other, thereby improving the efficiency of capacity changes and fault recovery in optical networks.

Implementation Method 1

WSS-controlled bundling

Methodology Applied
Scientific EffectWavelength Selective Switching: Filter (optical)

Implementation Method 2

pre-amplifiers, post-amplifiers, and intermediate line amplifiers

Methodology Applied
Scientific EffectOptical Amplification: Electromagnetic Induction

Implementation Method 3

Amplified Spontaneous Emission (ASE) channel holders

Methodology Applied
Scientific EffectAmplified Spontaneous Emission: Light

Implementation Method 4

The interleaving bundling approach suffers from Stimulated Raman Scattering (SRS) penalties

Methodology Applied
Scientific EffectStimulated Raman Scattering: Scattering

Data Source

PatentEP3891913B1Swapping bundles of optical channels in a c+l band system based on frequency band sensitivity
Publication Date: 2022.09.21 CIENA CORP
  • EP3891913B1 patent drawingFigure 1
  • EP3891913B1 patent drawingFigure 2
  • EP3891913B1 patent drawingFigure 3

AI summary

Systems, methods, and non-transitory computer-readable media are provided for performing channel swapping techniques for swapping bundles of optical channels in an optical network, such as a C+L band system, based on frequency band sensitivity. In one embodiment, a method includes swapping a first group of channels or first portion of spectrum in a more-sensitive frequency band with a first set of replacement channels or first portion of replacement spectrum using a first swapping technique. The method also includes swapping a second group of channels or second portion of spectrum in a less-sensitive frequency band with a second set of replacement channels or second portion of replacement spectrum using a second swapping technique that is different from the first swapping technique. The first and second swapping techniques are based at least in part on the number of channels or portion of spectrum that can be swapped at any given time instance.