Optical Spectrum Prediction for Layer 0 Capacity Changes

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Solution Overview

Problem

In Layer 0 optical networks, the time required for channel additions or deletions is slow due to the need to minimize power and OSNR impacts on in-service channels, primarily caused by non-linear gain transfers from Stimulated Raman Scattering and Spectral Hole Burning, leading to sequential or pseudo-sequential capacity changes.

Innovation Solution

A method to predict optical spectral profiles in advance of capacity changes by modeling current and future spectral loading states, accounting for effects like SRS, SHB, amplifier gain ripple, and tilt, allowing for proactive adjustments to actuators to achieve optimized spectral loading without using 'dummy' channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If channel additions are performed sequentially or pseudo-sequential to minimize power and OSNR impacts on in-service channels, then stability of in-service channels is maintained, but channel add time increases significantly

Engineering Contradiction:

Improvestability of in-service channelsVSAvoidchannel add time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary calculation of optimal attenuation targets for all OMS sections before executing channel additions. By computing the complete attenuation profile in advance based on the new channel configuration, the system can then apply all attenuation changes simultaneously, eliminating the need for sequential adjustments while maintaining stability through pre-calculated optimal settings.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses a computational model to calculate what the attenuation targets should be for the new channel configuration. This model copies the physical system's behavior mathematically, allowing the controller to determine optimal settings without physically testing each configuration, thus enabling fast parallel reconfiguration while maintaining stability.

Inventive Principle:

Principle #26Copying

2Loss of time

If attenuation targets are preset to achieve fast capacity change without considering nonlinear gain transfers, then channel add time is reduced, but performance accuracy deteriorates due to incorrect attenuation settings

Engineering Contradiction:

Improvechannel add timeVSAvoidattenuation target accuracy

Core Design Contradiction:

Loss of timeVSManufacturing precision

Solution Approach 1:

The system incorporates nonlinear gain transfer effects (SRS, SHB) into the attenuation target calculation by adjusting the parameters used in the computation. Instead of using simple linear models, the system modifies the calculation to account for these nonlinear effects, thereby achieving both fast reconfiguration and accurate attenuation settings that maintain optimal performance.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If incremental power-add steps with control algorithms are used to minimize steady-state power offsets, then power stability is improved, but the time required for channel addition increases to seconds or tens of seconds

Engineering Contradiction:

Improvepower stabilityVSAvoidchannel add time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system calculates the optimal attenuation targets for all OMS sections in advance, before channel additions are executed. This preliminary calculation determines the exact attenuation settings needed to maintain power stability, allowing all changes to be applied simultaneously rather than through incremental steps, thus achieving both stability and speed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces the physical trial-and-error process of incremental power adjustments with a computational model that calculates optimal settings directly. This substitution of mathematical calculation for physical experimentation eliminates the time required for iterative control algorithm execution while maintaining power stability through accurately predicted optimal settings.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables path-independent Layer 0 timing for capacity changes, reducing restoration time to seconds while maintaining stability and avoiding performance impacts on in-service channels, independent of the number of OADM hops.

Implementation Method 1

the steady-state power offsets (overshoots or undershoots from their optimal launch power targets to the fibers), and hence, OSNR impact on the in-service channels due to non-linear gain transfers over the photonic section due to Stimulated Raman Scattering (SRS) in optical fibers

Methodology Applied

Scientific EffectStimulated Raman Scattering:

Implementation Method 2

Methodology Applied

Scientific EffectSpectral Hole Burning:

Data Source

PatentUS20190253361A1Predicting optical spectral profiles in advance of capacity changes in optical networks

Publication Date: 2019.08.15 CIENA CORP

AI summary

Systems and methods for preconditioning an optical spectrum through predicting optical spectral profiles in advance of capacity changes in an optical section include obtaining data associated with the optical section to model a current state of spectral loading in the optical section; responsive to a proposed capacity change in the current state of spectral loading, estimating a future state of spectral loading which includes the capacity change; and causing changes to one or more settings in the optical section to achieve an optimized spectral loading for the future state of spectral loading.