OTDR Fiber Measurement Using Attenuation Modulation

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Solution Overview

Problem

Current optical time domain reflectometer (OTDR) systems face challenges in measuring individual fiber links within multiple fiber links without increasing system performance costs, as they receive mixed reflected light from multiple channels, making it difficult to accurately represent characteristics of a single fiber link.

Innovation Solution

The method involves performing multiple OTDR detections with attenuation modulation on light entering each fiber link, allowing for the acquisition of total fiber curves, which are then used to calculate separate fiber curves for each link through a preset algorithm, enabling the measurement of a single fiber link within multiple links with reduced system performance impact and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple fiber links are measured simultaneously by OTDR detection apparatus, then measurement efficiency is improved, but measurement precision deteriorates due to mixed reflected light from multiple channels

Engineering Contradiction:
Improvemeasurement efficiencyVSAvoidfiber curve accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent divides the measurement process into multiple separate detection instances, each targeting a specific fiber link. By performing N times of fiber detection with attenuation modulation, the system segments the mixed reflected light into distinct components that can be separately analyzed and reconstructed to obtain individual fiber curves for each link.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the attenuation parameter of light entering different fiber links during the detection process. By applying attenuation modulation with different modulation parameters for different fiber links across multiple detection instances, the system creates distinguishable signal characteristics that enable precise separation and measurement of individual fiber link properties.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If separate OTDR detection apparatus and auxiliary apparatus are disposed on each fiber link, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvesingle fiber link measurement accuracyVSAvoidsystem configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes a single OTDR detection apparatus capable of measuring multiple fiber links by implementing a multi-functional measurement system. The apparatus performs N times of fiber detection on N different fiber links using attenuation modulation, eliminating the need for separate detection apparatus on each link while maintaining measurement precision through mathematical separation of the mixed signals.

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

Solution Approach 2:

The patent introduces attenuation modulation as an intermediary mechanism to enable single-apparatus measurement of multiple fiber links. The modulation apparatus acts as a mediator that applies controlled attenuation to light entering different fiber links, creating distinguishable signal patterns that allow the single OTDR detection apparatus to separately identify and measure each fiber link's characteristics.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If separate OTDR detection apparatus are disposed on each fiber link, then measurement precision is improved, but loss of time increases due to separate measurement processes

Engineering Contradiction:
Improveindividual fiber curve accuracyVSAvoidtotal measurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements continuous measurement by having the single OTDR detection apparatus perform N times of fiber detection on N different fiber links in sequence. The measurement process continues without interruption, with each detection instance targeting a different fiber link using attenuation modulation, thereby obtaining all individual fiber curves in one continuous operation rather than requiring separate measurement sessions.

Inventive Principle:
Principle #20Continuity of useful 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

This approach allows for accurate measurement of individual fiber links in multiple fiber link systems with minimal system performance impact and cost, by using attenuation modulation to differentiate and calculate separate fiber curves from total fiber curves acquired during OTDR detection.

Implementation Method 1

An optical time domain reflectometer (Optical Time Domain Reflectometer, OTDR for short) is a precision optoelectronic integrated instrument made according to back scattering that is generated from Rayleigh scattering and Fresnel reflection when a light ray is transmitted in a fiber.

Methodology Applied
Scientific EffectRayleigh scattering: Rayleigh Scattering

Implementation Method 2

An optical time domain reflectometer (Optical Time Domain Reflectometer, OTDR for short) is a precision optoelectronic integrated instrument made according to back scattering that is generated from Rayleigh scattering and Fresnel reflection when a light ray is transmitted in a fiber.

Methodology Applied
Scientific EffectFresnel reflection: Reflection

Data Source

PatentEP3252427B1Optical fiber measuring method, device and system
Publication Date: 2019.03.27 HUAWEI TECH CO LTD
  • EP3252427B1 patent drawingFigure 1
  • EP3252427B1 patent drawingFigure 2
  • EP3252427B1 patent drawingFigure 3~4

AI summary

Embodiments of the present invention provide a fiber measurement method, apparatus, and system. The fiber measurement method of the present invention includes: acquiring a detection control parameter sent by a control and communications apparatus; performing N times of fiber detection according to a fiber detection distance, duration, and an optical pulse width, to acquire N total fiber curves by means of collection, and for at least N-1 times of fiber detection, each time fiber detection is performed, first performing, by using a modulation apparatus according to a modulation parameter, attenuation modulation on light that is about to enter a to-be-detected fiber, where to-be-detected fiber links corresponding to light that is modulated each time are different; and calculating by using a preset curve algorithm according to the N total fiber curves and the modulation parameter, to acquire respective fiber curves of N to-be-detected fiber links, and feeding back the fiber curves to the control and communications apparatus. The embodiments of the present invention implement measurement of a single fiber link in multiple fiber links, and reduce impact on system performance as much as possible.