Optical Network Node Chromatic Dispersion Compensation

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Solution Overview

Problem

Optical ring networks face challenges with chromatic dispersion causing time delays and overlap of optical data packets from different wavelengths, leading to inefficiencies and power gaps that affect amplifiers and signal quality.

Innovation Solution

An optical network node that detects and terminates optical data packets at specific wavelengths, replacing them with new packets containing transmission data or dummy data to maintain synchronization and prevent power gaps, thereby avoiding the need for costly hub nodes and minimizing ASE noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If optical data packets are transmitted at different wavelengths without regeneration, then transmission distance is extended and hub nodes are avoided, but chromatic dispersion causes time delays and packet overlap

Engineering Contradiction:
Improvetransmission distanceVSAvoidpacket synchronization
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The invention divides the optical ring network into segments with individual wavelength regeneration points at regular intervals. Instead of requiring a single hub node to regenerate all wavelengths, each segment independently regenerates packets at its assigned wavelengths, breaking the long transmission distance into manageable segments that maintain synchronization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention performs preliminary wavelength assignment and packet regeneration at designated nodes before packets travel long distances. By pre-configuring which nodes regenerate which wavelengths and inserting synchronization markers in advance, the system prevents chromatic dispersion-induced overlap before it occurs.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If optical data packets are terminated and replaced at each node, then packet overlap is prevented, but power gaps affect amplifiers and signal quality

Engineering Contradiction:
Improvepacket synchronizationVSAvoidpower gaps
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention maintains continuous optical power by ensuring that when one data packet is terminated, another packet (or dummy data) immediately fills the time slot. This continuous transmission prevents power gaps that would otherwise cause amplifier instability and signal quality degradation.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The invention uses dummy data packets as intermediaries to fill time slots when actual data packets are terminated. These dummy packets maintain the optical power continuity required by amplifiers while allowing legitimate data packets to be dropped at their destination nodes without causing power gaps.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If hub nodes are used to regenerate all wavelengths, then packet synchronization is maintained, but device complexity and cost increase

Engineering Contradiction:
Improvepacket synchronizationVSAvoidnetwork structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention segments the wavelength regeneration function across multiple distributed nodes rather than concentrating it in a single hub node. Each node handles regeneration for specific wavelengths in its segment, reducing the complexity and cost of individual nodes while maintaining overall synchronization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention makes regular optical network nodes multi-functional by enabling them to perform wavelength-specific packet regeneration in addition to their standard routing functions. This eliminates the need for dedicated hub nodes, as regular nodes can serve multiple purposes including regeneration, routing, and monitoring.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2747324B1Optical network node for an optical ring network
Publication Date: 2015.04.01 ALCATEL LUCENT SA
  • EP2747324B1 patent drawingFigure 1~2
  • EP2747324B1 patent drawingFigure 3
  • EP2747324B1 patent drawingFigure 4

AI summary

Proposed is an optical network node for an optical ring network, which counteracts the effects of different chromatic dispersions at different time delays affecting different optical TSM signals of different respective wavelengths in an improved manner.