Remote Optical Network Terminal Detection via Polarization Reflections

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Solution Overview

Problem

Current methods fail to efficiently detect active optical network terminals (ONTs) at customer premises, especially when they are not synchronized with the operator's headend, leading to resource wastage and inefficient network management.

Innovation Solution

A remote detection device is used at the optical terminal box (OTB) to identify ONTs by transmitting optical signals with varying polarizations and measuring reflected power, determining the presence of ONTs based on polarization-dependent reflections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If optical signals are transmitted through fiber optic drop lines to detect ONTs, then detection capability is improved, but polarization-dependent losses and reflections cause measurement inaccuracies

Engineering Contradiction:
ImproveONT detection capabilityVSAvoidreflected power measurement accuracy
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by systematically varying the polarization state of the transmitted optical signal. The detection device transmits optical signals with different polarization orientations (e.g., horizontal, vertical, diagonal) and measures the reflected power for each polarization state. This allows the system to identify polarization-dependent variations caused by ONT connections and compensate for them through algorithmic analysis, thereby resolving the measurement accuracy issue while maintaining detection capability.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If fiber optic drop lines are left connected at OTB ports for shared infrastructure, then network adaptability is improved, but resource management efficiency deteriorates due to inability to distinguish active from inactive connections

Engineering Contradiction:
Improvenetwork sharing capabilityVSAvoidresource management efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent implements self-service by enabling the network infrastructure to automatically identify and distinguish between active and inactive ONT connections. The detection device autonomously transmits optical signals through each drop line, analyzes the reflected power characteristics, and determines whether an ONT is actually connected without requiring manual intervention or physical disconnection of cables. This allows the system to maintain shared infrastructure adaptability while achieving automated resource management efficiency.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If manual checking of ONT connections is performed by physically disconnecting drop lines, then detection accuracy is improved, but operational complexity and time consumption increase

Engineering Contradiction:
Improveconnection status detection accuracyVSAvoiddetection process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical approach of physically disconnecting and reconnecting drop lines with an optical field-based detection method. Instead of manual mechanical operations, the system uses optical signals transmitted through the existing connections to detect ONT presence by analyzing reflected power characteristics. This substitution eliminates the need for physical disconnection while maintaining detection accuracy, thereby reducing operational complexity and time consumption.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If optical signals with varying polarizations are transmitted to detect ONTs, then detection reliability is improved, but energy consumption increases

Engineering Contradiction:
ImproveONT detection reliabilityVSAvoiddetection device energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by transmitting optical signals with varying polarizations in a structured, periodic sequence rather than continuously. The detection device systematically cycles through different polarization states (e.g., horizontal, vertical, diagonal) and measures reflected power at each stage. This periodic approach ensures reliable detection by sampling multiple polarization states while minimizing energy consumption by avoiding continuous transmission, thereby resolving the contradiction between reliability and energy efficiency.

Inventive Principle:
Principle #19Periodic action

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

Accurately identifies ONTs connected to fiber optic drop lines, enabling operators to disconnect unused lines and optimize resource usage by distinguishing between active and inactive connections.

Implementation Method 1

Transmitting by an optical device connected to the fiber optic drop line, a first optical signal having a given wavelength with a first polarization, through the fiber optic drop line; Transmitting by the optical device, through the fiber optic drop line, a second optical signal having the given wavelength with a second polarization different from the first polarization

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

Measuring by the optical device, the optical power of the reflected first optical signal received through the fiber optic drop line; Measuring by the optical device, the optical power of the reflected second optical signal received through the fiber optic drop line

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4064587B1Optical device, method and system for remotely detecting optical network terminals
Publication Date: 2025.07.16 TELEFONICA SA
  • EP4064587B1 patent drawingFigure 1
  • EP4064587B1 patent drawingFigure 2
  • EP4064587B1 patent drawingFigure 3

AI summary

Device, method and system for the detection of user optical terminal equipments (for example ONTs) of a customer fiber optic distribution network that allows remotely detecting, from the optical terminal box (OTB), if there is a terminal equipment at the user's premises that is optically connected, whether or not it is turned on. In other words, the proposed solution allows, remotely and independently of the transmission system being used, to detect and identify from the operator's optical terminal box, which fiber optic drop lines (connections) actually end up in an optical rosette at the customer's premises that has an ONT optically connected, whether or not it is electrically powered.