Embedded Optical Reflectors for Connector Loss Quantification

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Solution Overview

Problem

Field-fit optical connectors in FTTP systems face challenges in quality assurance due to the lack of reliable confirmation methods, leading to potential faults and excessive losses, making it difficult to detect and measure optical losses accurately in the field.

Innovation Solution

An optical fibre with embedded optical reflectors distributed along its length allows for the measurement of optical signal reflections to quantify connector losses by comparing the power levels of the inserted and reflected signals, enabling accurate and convenient verification of connector installation without requiring actions at the exchange or intermediate locations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional optical power measurement methods are used to measure connector loss, then measurement can be performed, but the measurement requires action at both distribution point and customer premises which is time-consuming and complex

Engineering Contradiction:
Improveconnector loss measurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The measurement function is extracted from the distributed measurement system and consolidated into a single portable measurement device that can be deployed at the customer premises only. The embedded reflectors enable the device to perform bidirectional measurements independently without requiring coordination at the distribution point.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Embedded optical reflectors are introduced as intermediaries within the fibre to enable the measurement device to send test signals and receive reflected signals through the same connector interface. This intermediary mechanism allows single-location measurement while maintaining measurement accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If field-fit connectors are used to enable quick connection at customer premises, then installation speed is improved, but quality assurance becomes problematic and faults are difficult to detect

Engineering Contradiction:
Improveconnector installation speedVSAvoidconnector quality assurance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The embedded optical reflectors provide a feedback mechanism that enables the measurement device to receive reflected test signals from the connector interface. This feedback loop allows immediate verification of connector quality and detection of faults such as gaps, misalignment, or contamination, while maintaining the speed benefits of field-fit installation.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If optical power readings are taken from distribution point to quantify connector loss, then loss estimation is possible, but the process is time-consuming especially when distribution point is remote from customer premises

Engineering Contradiction:
Improveconnector loss quantificationVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The measurement system performs self-service measurements at the customer premises using the embedded reflectors as reference targets. The portable measurement device independently completes the entire measurement process locally without requiring personnel to travel to or coordinate with the remote distribution point, significantly reducing measurement time while maintaining accuracy.

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 method simplifies and enhances the accuracy of loss measurement, allowing field engineers to quickly verify correct connector installation and reduce the process steps for installing drop fibres to customer premises, while minimizing the impact of fibre losses on measurement accuracy.

Implementation Method 1

measuring a component of the optical signal reflected by at least one of the plurality of embedded optical reflectors

Methodology Applied
Scientific EffectOptical reflection: Reflection

Data Source

PatentEP3655746B1A method of quantifying loss associated with an optical connector connected to an end of an optical fibre
Publication Date: 2025.01.08 BRITISH TELECOM PLC
  • EP3655746B1 patent drawingFigure 1~2
  • EP3655746B1 patent drawingFigure 3~8
  • EP3655746B1 patent drawingFigure 4~5

AI summary

An optical fibre comprising a plurality of embedded optical reflectors distributed periodically along the length of the fibre and a method of quantifying loss associated with an optical connector that is connected to optical fibre comprising a plurality of embedded optical reflectors distributed periodically along the length of the fibre. The method comprises: inserting an optical signal into the fibre through the optical connector; measuring a component of the optical signal reflected by at least one of the plurality of embedded optical reflectors, in which the component is received through the optical connector; calculating the difference in power level between the inserted and reflected signals; and quantifying, based on the calculated power level difference and the reflectivity of the embedded optical reflector, the loss associated with the optical connector.