Optical Network Node Power Status Detection Using Reflective Switch

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In optical networks, particularly in access networks, there is a need to efficiently diagnose the cause of connection losses to remote nodes without physically dispatching engineers, especially when the nodes are unable to send or receive signals, due to the limitations of existing methods like the 'dying gasp' signal which is unreliable and does not allow for constant monitoring.

Innovation Solution

An optical signal is directed to a reflector based on the power status of the remote node, using a switch, allowing for reliable indication of connection loss causes, including power-down scenarios, without requiring the node to be powered up, and continuous monitoring of the link for real-time responses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional methods like 'dying gasp' signal are used to detect connection loss, then some fault information can be obtained, but the detection is unreliable and does not allow for constant monitoring

Engineering Contradiction:
Improvefault detection reliabilityVSAvoidresponse time to faults
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary action by continuously monitoring the optical link using OTDR measurements even before connection loss occurs. The baseline OTDR trace is established during normal operation, enabling the system to detect faults immediately when they happen rather than waiting for the node to send a dying gasp signal.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuity of useful action through constant monitoring of the optical link using periodic OTDR measurements. This continuous surveillance ensures that connection losses are detected immediately when they occur, eliminating the gaps inherent in event-driven approaches like dying gasp signals.

Inventive Principle:
Principle #20Continuity of useful action

2Measurement precision

If engineers are dispatched to physically diagnose connection issues, then accurate fault identification can be achieved, but the cost and time increase significantly

Engineering Contradiction:
Improvefault identification accuracyVSAvoidtime for fault diagnosis
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system applies self-service by enabling automatic fault identification through OTDR analysis. The network management system automatically compares current OTDR measurements against baseline traces, identifies structural causes of connection loss, and determines whether engineer dispatch is necessary, reducing reliance on manual field diagnostics.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses feedback by continuously monitoring the optical link and automatically analyzing OTDR measurements. When connection loss is detected, the system immediately compares the current trace with the baseline to identify structural faults, providing real-time feedback that eliminates the need for delayed manual diagnosis.

Inventive Principle:
Principle #23Feedback

3Difficulty of detecting and measuring

If structural causes of connection loss are investigated, then physical faults can be identified, but the process requires engineer dispatch which is costly and time-consuming

Engineering Contradiction:
Improvedetection of structural faultsVSAvoidcomplexity of diagnosis system
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The system applies universality by making the OTDR measurement system serve multiple functions: it continuously monitors link quality, establishes baseline traces during normal operation, detects connection losses, and identifies structural faults all through the same measurement infrastructure, eliminating the need for separate diagnostic equipment.

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

Solution Approach 2:

The system uses an intermediary approach by introducing automated OTDR analysis as a mediator between connection loss detection and engineer dispatch. The baseline OTDR trace serves as an intermediary reference that enables automatic identification of structural faults, reducing the need for complex manual diagnostic procedures.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enables cost-efficient and reliable remote detection of connection issues, reducing unnecessary engineer dispatches and enabling quick responses to faults, especially in reverse-powered nodes, by using a micro-electromechanical systems switch and reflectors like Fibre Bragg Gratings to confirm power status and structural integrity of the optical link.

Implementation Method 1

An optical signal transmitted to an optical network node over an optical link can be received by the node along as the structure of the link to the node does not include physical discontinuities. The RN need not be powered on to receive the optical signal. A switch directs the signal received at the RN to a reflector in dependence on the power status of the RN.

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

using a micro-electromechanical systems switch and reflectors like Fibre Bragg Gratings to confirm power status and structural integrity of the optical link

Methodology Applied
Scientific EffectBragg Diffraction: Bragg Diffraction

Data Source

PatentEP3189601B1Optical network fault identification
Publication Date: 2023.08.02 BRITISH TELECOM PLC
  • EP3189601B1 patent drawingFigure 1~2B
  • EP3189601B1 patent drawingFigure 3
  • EP3189601B1 patent drawingFigure 4~5

AI summary

An optical network node capable of being powered, comprising - a reflector arranged to reflect an optical signal, and - a switch arranged to direct the optical signal to the reflector in dependence on whether the optical network node is powered.