Optical Repeater Supervisory Circuit for Dual-Wavelength Path Monitoring

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Solution Overview

Problem

Subsea network operators face challenges in optimizing the capacity and performance of fiber-optic cable plants to handle increasing bandwidth demands, requiring fast fault detection, improved maintainability, and upgradable capacity while maintaining low-cost implementation and maintenance.

Innovation Solution

A bidirectional optical repeater with two unidirectional optical amplifiers and a supervisory optical circuit that uses dual supervisory wavelengths to monitor and characterize the input and output of optical amplifiers, enabling simultaneous monitoring of communication and monitoring signals across optical paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If single supervisory wavelength is used to monitor optical amplifiers, then monitoring simplicity is improved, but simultaneous monitoring of both amplifiers cannot be achieved

Engineering Contradiction:
Improvemonitoring simplicityVSAvoidsimultaneous monitoring capability
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent divides the monitoring function into two separate supervisory wavelengths (first supervisory wavelength for first optical amplifier, second supervisory wavelength for second optical amplifier). This segmentation allows independent monitoring of each amplifier without interference, enabling simultaneous monitoring of both amplifiers while maintaining operational simplicity through dedicated wavelength assignment.

Inventive Principle:
Principle #1Segmentation

2Productivity

If dual supervisory wavelengths are used to monitor both amplifiers simultaneously, then simultaneous monitoring capability is improved, but wavelength management complexity increases

Engineering Contradiction:
Improvesimultaneous monitoring capabilityVSAvoidwavelength management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a supervisory optical circuit that handles multiple functions: it monitors both the first and second optical amplifiers simultaneously using different wavelengths, provides fault detection, and enables performance characterization. This multi-functionality consolidates what would otherwise require separate monitoring systems into a single integrated circuit, managing the complexity through unified design.

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

3Reliability

If comprehensive monitoring of optical paths is implemented, then fault detection capability is improved, but system complexity increases

Engineering Contradiction:
Improvefault detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The supervisory optical circuit is designed to be self-contained within the optical repeater, automatically monitoring the optical paths without requiring external monitoring equipment. The circuit inherently provides fault detection and performance characterization functions, allowing the system to monitor itself and reducing overall system complexity while maintaining comprehensive fault detection capability.

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 solution allows for efficient fault detection and performance characterization of optical repeaters, ensuring reliable operation and cost-effective maintenance of subsea fiber-optic networks by enabling simultaneous monitoring of communication and monitoring signals across optical paths.

Implementation Method 1

each optical path includes multi-wavelength optical fibers connected end-to-end by one or more optical repeaters that amplify the optical signals

Methodology Applied
Scientific EffectOptical amplification:

Implementation Method 2

the optical paths can also carry monitoring signals such as supervisory signals in one of two designated supervisory wavelengths

Methodology Applied
Scientific EffectOptical signal transmission: Optical Fibre

Data Source

PatentEP3771116B1Technique for monitoring optical paths
Publication Date: 2024.07.10 ALCATEL SUBMARINE NETWORKS
  • EP3771116B1 patent drawingFigure 1
  • EP3771116B1 patent drawingFigure 2
  • EP3771116B1 patent drawingFigure 3

AI summary

An optical repeater, having two optical amplifiers (OAs) for two optical paths, has optical pathways for providing, for each OA, looped-back incoming and amplified outgoing supervisory signals of the same wavelength but separated in time to enable independent characterization of the amplitudes of the incoming and amplified outgoing supervisory signals. When configured to operate with two different supervisory wavelengths, one for each OA, both OAs can be characterized simultaneously by two different landing stations, each transmitting a supervisory signal having a different supervisory wavelength.