Optical Network Section Health Validation via Pilot Signals

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Solution Overview

Problem

Dark sections in optical networks, which are not visible to the network management layer, pose challenges due to unidentified potential problems such as high loss, reflections, and component malfunctions, leading to reliability issues and increased network response time during traffic setup or failure recovery.

Innovation Solution

A system and method that uses a controller to monitor the health of optical network sections by comparing input and output power levels across optical links, employing a light source to ensure sections are lit and validate their viability, thereby identifying and addressing issues proactively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If dark sections are used in optical networks, then network flexibility and cost are improved, but reliability and monitoring capability deteriorate

Engineering Contradiction:
Improvenetwork flexibilityVSAvoidnetwork reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary health validation of optical sections by injecting test signals before allowing traffic to be established. This advance checking ensures that sections are verified to be free of defects such as high loss, reflections, and component malfunctions before they are activated for normal use, thereby maintaining reliability while allowing dark section deployment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A photonic management layer acts as an intermediary between the optical transport layer and the control layer. This intermediary continuously monitors optical section health using test signals and provides visibility into previously dark sections, enabling reliable detection of problems without requiring permanent traffic channels.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If dark sections are used in optical networks, then initial deployment cost is reduced, but network response time during failure recovery increases

Engineering Contradiction:
Improvetraffic channelsVSAvoidnetwork response time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The system continuously pre-validates optical section health by injecting test signals even when no traffic is present. This ensures that when failures occur and recovery is needed, the system already has current health information about alternative paths, enabling rapid restoration without waiting for channel establishment latency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The photonic management layer provides continuous feedback about optical section health status to the control layer. This real-time information allows the system to make immediate routing decisions during failure recovery, eliminating the need to wait for traffic channels to be established before detecting section problems.

Inventive Principle:
Principle #23Feedback

3Reliability

If continuous monitoring of optical sections is implemented, then reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvesection monitoring capabilityVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses universal test signal injection and detection mechanisms that can monitor all optical sections regardless of whether they carry traffic. The same photonic management layer infrastructure handles both monitored and unmonitored sections, eliminating the need for separate monitoring hardware and reducing overall system complexity.

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

Solution Approach 2:

The optical sections themselves provide monitoring information through their natural optical characteristics. By injecting test signals and measuring their transmission properties, the system uses the sections' own optical properties for self-diagnosis, eliminating the need for external complex monitoring equipment.

Inventive Principle:
Principle #25Self-service

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 minimizes network downtime and outage by ensuring optical sections are validated before further actions, enabling efficient re-routing or adding new WDM channels, thus enhancing network reliability and reducing restoration time.

Implementation Method 1

instruct at least a first light source corresponding to the first ROADM and at least a second light source corresponding to the second ROADM to respectively send a first pilot optical signal and a second pilot optical signal along the optical link

Methodology Applied
Scientific EffectOptical signal transmission: Optical Fibre

Data Source

PatentEP3580864B1System and method of providing dark section free transport networks
Publication Date: 2023.10.04 HUAWEI TECH CO LTD
  • EP3580864B1 patent drawingFigure 1~2
  • EP3580864B1 patent drawingFigure 3~4
  • EP3580864B1 patent drawingFigure 5~6

AI summary

A wavelength selective switch (WSS), reconfigurable optical add-drop multiplexer (ROADM) and methods of determining a condition of a domain network section are provided. The WSS and ROADM include a light source for sending an optical signal having a characteristic. The method comprises instructing a light source to send an optical signal across an optical link, obtaining measurements of characteristic values of the optical signal received at and sent by components along the domain network section, comparing the characteristic values to pre-defined limits, and determining the condition of the domain network section based on the characteristic values.