Remote Optically Pumped Amplifier Pump Power Multiplexing

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Solution Overview

Problem

Optical communication networks face challenges in amplifying optical signals over long, lossy optical spans without the need for electrical power or regeneration points, particularly in unrepeatered systems where active optical repeaters are not feasible.

Innovation Solution

The implementation of remote optically pumped amplifiers (ROPA) that use optical pumping to amplify signals, eliminating the need for electrical power and allowing for spatial and wavelength multiplexing of pump powers to efficiently amplify signals across optical links.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If active optical repeaters are used to amplify signals, then signal amplification is achieved, but electrical power and regeneration points are required

Engineering Contradiction:
Improvesignal amplification capabilityVSAvoidelectrical power requirement
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces active electronic repeaters with passive optical amplification using Raman scattering and erbium-doped fiber amplification. The mechanical/electronic system of active repeaters is substituted with optical field-based amplification mechanisms that do not require electrical power at the amplification point, thereby eliminating the need for electrical power and regeneration points while maintaining signal amplification capability

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

Solution Approach 2:

The optical fiber itself serves as the amplification medium through stimulated Raman scattering, where the fiber's nonlinear optical properties enable signal amplification without external power sources. The erbium-doped fiber section provides distributed gain using pump light transmitted through the same fiber, making the system self-sufficient without requiring separate power infrastructure

Inventive Principle:
Principle #25Self-service

2Device complexity

If optical spans are extended to reduce repeater points, then system complexity is reduced, but signal loss increases

Engineering Contradiction:
Improvenumber of repeater pointsVSAvoidoptical signal loss
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent changes the optical parameters of the fiber by doping it with erbium ions, which fundamentally alters the fiber's optical properties to provide gain. Additionally, pump power parameters are optimized to achieve distributed amplification along the span, enabling extended transmission distances without increasing the number of repeater points while compensating for signal loss

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The erbium-doped fiber is prepared in advance with specific erbium ion concentrations and pump power levels are pre-configured to provide distributed gain along the transmission path. This preliminary preparation enables the fiber to actively compensate for losses before they accumulate over extended spans, allowing longer distances between repeater points

Inventive Principle:
Principle #10Preliminary 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

ROPA systems effectively amplify optical signals over long distances without electrical power, supporting unrepeatered communication links and enabling efficient signal transmission in submarine and terrestrial optical communications, including multi-span systems, by utilizing optical pumping to enhance signal strength and reduce loss.

Implementation Method 1

a bypass filter configured to receive an optical signal and first pump power and to separate the optical signal and the first pump power

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

remote optically pumped amplifiers (ROPA) that use optical pumping to amplify signals

Methodology Applied
Scientific EffectOptical pumping:

Implementation Method 3

an amplifier configured to receive the optical signal from the bypass filter and to amplify the optical signal

Methodology Applied
Scientific EffectStimulated emission:

Implementation Method 4

an optical combiner/multiplexer configured to receive the first pump power from the bypass filter, receive at least second and third pump powers, combine at least two of the first, second and third pump powers

Methodology Applied
Scientific EffectWavelength multiplexing:

Data Source

PatentEP3266125B1Optical transmission system and related remote optically pumped amplifier (ROPA) and method
Publication Date: 2020.04.22 NEPTUNE SUBSEA IP LTD
  • EP3266125B1 patent drawingFigure 1~3
  • EP3266125B1 patent drawingFigure 4~5
  • EP3266125B1 patent drawingFigure 6~7

AI summary

An apparatus includes a remote optically pumped amplifier (ROPA) (110, 112, 130, 132, 200, 300, 400, 500, 600, 700, 800, 900, 1014, 1018, 1308a-1308m). The ROPA includes a bypass filter (204, 304, 804a, 804b, 904a, 904b, 1104, 1204a, 1204b) configured to receive an optical signal and first pump power and to separate the optical signal and the first pump power. The ROPA also includes an amplifier (206, 306, 806a, 806b, 906a, 906b, 1106, 1206a, 1206b) configured to receive the optical signal from the bypass filter and to amplify the optical signal. The ROPA further includes an optical combiner/multiplexer (208, 308, 402-404, 502-504, 602-604, 702-704, 808, 908, 1102c and 1120) configured to receive the first pump power from the bypass filter, receive at least second and third pump powers, combine at least two of the first, second and third pump powers, and provide different pump powers or combinations of pump powers to different locations within the ROPA to feed the amplifier.