OTDR Event Targeting via Dual Pulse Width Acquisition

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Solution Overview

Problem

Current Optical Time-Domain Reflectometry (OTDR) technologies face challenges in efficiently characterizing optical fiber links, particularly in high-volume testing environments like data centers, where long acquisition times are required for detailed characterization, leading to issues with event detection and spatial resolution, and existing methods cannot accurately assess individual events along the fiber link.

Innovation Solution

An OTDR method and device that performs an initial fast acquisition with long pulses for initial assessment, followed by a second acquisition with optimized parameters for specific events, allowing for real-time monitoring and detailed characterization of target events, thereby improving spatial resolution and reducing false failure indications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple acquisitions with different pulse widths are performed for detailed characterization, then measurement precision is improved, but acquisition time increases

Engineering Contradiction:
Improveevent detection precisionVSAvoidacquisition time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the optical fiber link into multiple zones based on detected events. A first zone contains events of interest requiring detailed characterization, while a second zone contains events requiring only basic characterization. This segmentation allows the system to apply different measurement strategies to different portions of the link, reducing overall acquisition time while maintaining precision where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using shorter pulse widths specifically in the first zone where events require detailed characterization, while using longer pulse widths in the second zone for basic characterization. This localized approach to measurement quality ensures high precision is applied only where necessary, rather than uniformly across the entire link.

Inventive Principle:
Principle #3Local quality

2Productivity

If long pulse widths are used to minimize acquisition time, then productivity is improved, but measurement precision deteriorates

Engineering Contradiction:
Improvetesting throughputVSAvoidspatial resolution
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent divides the fiber link into zones with different measurement requirements. In zones requiring high spatial resolution (first zone), shorter pulse widths are used despite the longer acquisition time, while in zones where throughput is prioritized (second zone), longer pulse widths are used. This segmentation enables the system to achieve both high productivity and high precision in different locations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent dynamically changes the pulse width parameter based on the specific zone and events being measured. The system selects from multiple available pulse width settings, choosing shorter widths for detailed event characterization and longer widths for routine measurements, thereby optimizing the balance between productivity and precision for each measurement segment.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If shorter pulse widths are used for better spatial resolution, then measurement precision is improved, but acquisition time increases

Engineering Contradiction:
Improvespatial resolutionVSAvoidaveraging time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies shorter pulse widths only in the first zone where high spatial resolution is critical for characterizing specific events. In the second zone, longer pulse widths are used which require less averaging time. This segmentation minimizes the total acquisition time while maintaining high spatial resolution where events require detailed analysis.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies the principle of partial action by using high-resolution measurements (shorter pulses) only partially - specifically in the first zone where events of interest are located - rather than applying it to the entire link. This partial application of high-resolution measurement reduces the overall time penalty while maintaining precision where needed.

Inventive Principle:
Principle #16Partial or excessive action

4Reliability

If multiple acquisitions are performed for complete mapping, then reliability is improved, but productivity decreases

Engineering Contradiction:
Improvecharacterization accuracyVSAvoidtesting speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the characterization requirements into two levels: detailed characterization in the first zone containing events of interest, and basic characterization in the second zone. This segmentation allows the system to maintain high reliability for critical events while improving overall productivity by reducing the depth of characterization in less critical areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different characterization qualities to different zones. The first zone receives high-quality detailed characterization with multiple measurements, while the second zone receives standard basic characterization. This local differentiation of quality ensures reliability is maintained where events require accurate assessment while productivity is improved in areas where basic characterization suffices.

Inventive Principle:
Principle #3Local quality

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 enables faster characterization of optical fiber links with improved spatial resolution, reducing false failures and minimizing measurement time while ensuring thorough inspection of defects, thus enhancing the reliability of OTDR assessments in high-volume testing scenarios.

Implementation Method 1

OTDR is a diagnostic technique where light pulses are launched in an optical fiber link and returning light, arising from backscattering and reflections along the fiber link, is detected and analyzed

Methodology Applied
Scientific EffectBackscattering: Scattering

Implementation Method 2

returning light, arising from backscattering and reflections along the fiber link, is detected and analyzed

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3637082B1OTDR method targeting identified event
Publication Date: 2023.01.25 EXFO
  • EP3637082B1 patent drawingFigure 1A
  • EP3637082B1 patent drawingFigure 1B
  • EP3637082B1 patent drawingFigure 2

AI summary

There is provided an OTDR method and device for characterizing an optical fiber link. At least a first OTDR acquisition is performed toward the optical fiber link. From the at least one first OTDR acquisition, one or more events are identified along the optical fiber link and a value of at least one characteristic associated with each event is estimated. A second OTDR acquisition is performed toward the optical fiber link in order to target a specific event among the identified events. Values of one or more OTDR acquisition parameters for the second OTDR acquisition are determined such that the OTDR acquisition parameters comprise a second pulse width different from the first pulse width used in the first OTDR acquisition.