Undersea Optical Amplifier Assembly Using Distributed SOA Channels

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Solution Overview

Problem

The high cost and inefficiency of deploying traditional high-end optical amplifiers in undersea communication systems due to stringent electrical power limitations and the need for extensive copper wiring, which limits the number and effectiveness of repeaters in long-haul subsea environments.

Innovation Solution

The use of compact, low-cost semiconductor optical amplifiers (SOAs) in repeater stages, which operate at higher power efficiency and provide wider amplification bandwidth, reducing electrical requirements and enabling multiple SOAs to be combined for series or parallel amplification, thereby reducing the need for equalizers and minimizing size and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional high-end optical amplifiers are used in undersea communication systems, then signal amplification quality is maintained, but electrical power consumption increases and device cost increases

Engineering Contradiction:
Improvesignal amplification qualityVSAvoidelectrical power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the optical amplification function into multiple lower-power semiconductor optical amplifiers (SOAs) distributed along the fiber optic cable. Instead of using single high-power amplifiers, the system employs multiple SOAs that each provide partial amplification, collectively achieving the required signal strength while consuming less electrical power overall.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces traditional high-end optical amplifiers with semiconductor optical amplifiers (SOAs), substituting a different technological approach that achieves amplification through semiconductor physics rather than traditional optical amplifier mechanisms. This substitution enables lower power consumption while maintaining amplification functionality.

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

2Reliability

If traditional high-end optical amplifiers are used in undersea communication systems, then signal amplification quality is maintained, but device cost increases

Engineering Contradiction:
Improvesignal amplification qualityVSAvoiddevice cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs semiconductor optical amplifiers (SOAs) that are significantly cheaper than traditional high-end optical amplifiers. While individual SOAs have shorter operational lifetimes, their low cost allows for easier replacement and maintenance, reducing overall system cost while maintaining signal amplification quality through the use of multiple units.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent combines multiple semiconductor optical amplifiers into a single integrated module that can be deployed as one unit in the undersea environment. This merging approach reduces deployment complexity and overall cost compared to installing multiple separate high-end amplifiers, while achieving the required amplification through the combined effect of multiple SOAs.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If extensive copper wiring is used to power traditional optical amplifiers, then amplification function is achieved, but system complexity and deployment difficulty increase

Engineering Contradiction:
Improveamplification functionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the amplification function from centralized high-power amplifiers and distributes it to multiple smaller semiconductor optical amplifiers integrated along the fiber optic cable. This extraction eliminates the need for extensive copper wiring to power distant amplifiers, as each SOA can be powered locally with minimal wiring, significantly reducing system complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

4Device complexity

If the number of repeaters is limited due to power and wiring constraints, then deployment is simplified, but communication distance and effectiveness are reduced

Engineering Contradiction:
Improvedeployment simplicityVSAvoidcommunication distance
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The patent segments the amplification function into multiple distributed semiconductor optical amplifiers along the fiber optic cable. This segmentation allows the system to achieve long communication distances by providing distributed amplification at intervals, eliminating the need for fewer high-power amplifiers while maintaining signal quality over extended distances.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a centralized amplification approach (few amplifiers spaced far apart) to a distributed amplification approach (many amplifiers closely spaced along the cable). This dimensional change in the spatial distribution of amplifiers enables long communication distances while maintaining deployment simplicity, as the distributed SOAs can be integrated into the existing fiber infrastructure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 significantly reduces the electrical requirements and cost of subsea line deployments while maintaining desired bit-error-rates by distributing optical signal channels over multiple lower SNR SOA channels, achieving efficient long-haul communication with reduced attenuation and increased channel capacity.

Implementation Method 1

Each optical amplifier includes at least one semiconductor optical amplifier

Methodology Applied
Scientific EffectStimulated emission:

Implementation Method 2

a first waveguide external to each optical amplifier, internal to the PIC, and coupling each fiber optic input to each optical amplifier, and a second waveguide external to each optical amplifier

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3815268B1Low signal to noise ratio submarine communication system
Publication Date: 2023.09.06 GOOGLE LLC
  • EP3815268B1 patent drawingFigure 1
  • EP3815268B1 patent drawingFigure 2
  • EP3815268B1 patent drawingFigure 3A

AI summary

Systems and methods of undersea optical communication are provided. An undersea optical amplifier assembly can include a water-tight housing and a photonic integrated circuit disposed within the housing. The photonic integrated circuit includes a plurality of optical fiber inputs, each configured to receive an end of a respective optical fiber of a first fiber optic cable bundle, and a plurality of optical fiber outputs. Each optical fiber output corresponds to a respective optical fiber input to form a fiber optic input-output pair, and is configured to receive an end of a respective optical fiber of a second fiber optic cable bundle. The photonic integrated circuit includes an optical amplifier optically coupled to each respective fiber optic input-output pair. The housing includes a first water-tight access port configured to receive the first fiber optic cable bundle, and a second water-tight access port configured to receive a second fiber optic cable bundle.