Planar Lightwave Circuit Optical Amplifier Integration

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Erbium-doped fiber amplifiers (EDFAs) in optical transmission systems face challenges in reducing size, complexity, and cost while maintaining optical performance, with existing technologies limited by numerous discrete components and fiber loops, which hinder further performance improvements without increasing costs.

Innovation Solution

The use of planar lightwave circuits (PLCs) integrates WDM couplers and taps, eliminates fiber pigtails, and incorporates tunable optical components like Mach-Zehnder interferometers and gain flattening filters to reduce size and cost, while enhancing performance and control over key EDFA characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional discrete components and fiber loops are used in EDFAs, then optical performance can be maintained, but device complexity and size increase

Engineering Contradiction:

Improveoptical performanceVSAvoidnumber of discrete components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates multiple discrete optical components (WDM couplers, taps, isolators, photodiodes) onto a single planar lightwave circuit (PLC) substrate. This merging of components reduces the overall device complexity and size while maintaining the optical performance through controlled optical coupling between integrated elements.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The PLC substrate serves as a universal platform that performs multiple functions simultaneously: it acts as a mechanical support structure, an optical routing network, and an integration platform for various optical components. This multi-functionality eliminates the need for separate discrete components and their interconnecting fiber loops.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If more amplifier components are added to improve EDFA performance, then optical performance improves, but cost increases

Engineering Contradiction:

ImproveEDFA performanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By combining multiple optical components onto a single PLC substrate, the patent reduces the total component count and assembly requirements. This integration approach lowers manufacturing costs through economies of scale and reduced assembly complexity while maintaining enhanced EDFA performance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces traditional mechanical fiber optic assembly methods with integrated optical coupling on the PLC substrate. This substitution eliminates the need for precise mechanical alignment and manual assembly of discrete components, significantly reducing manufacturing costs and improving production efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If fiber pigtails are used for component coupling, then optical connections are established, but device size and complexity increase

Engineering Contradiction:

Improveoptical couplingVSAvoidfiber pigtail connections

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent integrates the coupling functions directly onto the PLC substrate, eliminating the need for external fiber pigtails. Optical components are coupled through controlled waveguide structures and coupling regions fabricated on the same substrate, reducing device complexity and improving reliability.

Inventive Principle:

Principle #5Merging (Combining)

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 the addition of new components at a small incremental cost, improving EDFA performance and reliability, and achieving considerable size and cost reductions while maintaining or improving optical performance characteristics.

Implementation Method 1

Each erbium doped fiber (EDF) is optically pumped by a semiconductor laser, so as to create a population inversion between energy states of the erbium ions comprising a gain medium of the EDF. Once the population inversion is created, the gain medium begins to amplify an optical signal propagating along the core of the EDF.

Methodology Applied

Scientific EffectStimulated emission:

Implementation Method 2

Each erbium doped fiber (EDF) is optically pumped by a semiconductor laser

Methodology Applied

Scientific EffectLight emission from semiconductor laser: Light Emitting Diode

Implementation Method 3

During the amplification process, the optical power of the pump is absorbed by the gain medium, which simultaneously amplifies all the optical channels present.

Methodology Applied

Scientific EffectAbsorption of optical energy: Absorption (EM radiation)

Data Source

PatentUS8462430B2Optical fiber amplifier and a control method therefor

Publication Date: 2013.06.11 WELLS FARGO BANK NA

AI summary

An optical amplifier having two erbium doped fiber coils and a pump laser diode is described. A tunable optical power splitter is used for variably splitting the optical pump power for the laser diode between the two erbium doped fiber coils, and variable tilters can be used for correcting the gain tilt of the amplifier. The variable splitter and the tilters can include thermally tunable Mach-Zehnder interferometers.