Optical Packet Switching Node Architecture for Scalable WDM Networks

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Solution Overview

Problem

Current optical packet switching nodes in WDM networks lack high connectivity, scalability, and efficiency due to excessive use of optical filters, limiting geographic connectivity and requiring more optical transponders for electronic conversion.

Innovation Solution

An optical packet switching node with a modular architecture that includes multiple inputs and outputs, using a combiner and gate system to selectively route wavelength channels with adjustable demultiplexers and multiplexers, minimizing filter usage and enabling flexible traffic processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional optical packet switching nodes use multiple optical filters in cascade for traffic processing, then wavelength channel separation and routing can be achieved, but the geographic connectivity of the node is unnecessarily constrained and device complexity increases

Engineering Contradiction:
Improvegeographic connectivityVSAvoidnumber of optical filters
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the wavelength selection function from traditional cascade optical filters and implements it through electronic control of optical gates. The controller receives routing information, determines the appropriate output port for each wavelength channel, and electronically configures optical gates to route wavelengths without requiring multiple physical filters in cascade, thereby reducing filter usage and increasing geographic connectivity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/optical filter-based wavelength routing system with an electronically controlled optical gate system. Instead of using physical filter assemblies that constrain connectivity, the invention uses electronic signals to control optical gates, substituting mechanical filtering with electronic routing decisions that can adapt to any geographic configuration

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

2Adaptability or versatility

If optical packet switching nodes convert all incoming traffic to electronic domain for processing, then traffic manipulation flexibility is improved, but the number of optical transponders required increases cost

Engineering Contradiction:
Improvetraffic processing flexibilityVSAvoidnumber of optical transponders
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent segments traffic processing into two paths: optical circuit traffic that passes through transparently without electronic conversion, and optical packet traffic that undergoes electronic processing. This segmentation allows the node to handle different traffic types appropriately, maintaining flexibility for packet manipulation while avoiding unnecessary electronic conversion of circuit traffic, thus reducing the number of optical transponders required

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The optical gates serve multiple functions: they can route optical circuit traffic transparently, route optical packet traffic for electronic processing, and dynamically reconfigure based on traffic type and routing requirements. This multi-functionality eliminates the need for separate dedicated transponders for different traffic handling modes

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

3Ease of manufacture

If optical packet switching nodes are designed with fixed architecture, then manufacturing cost is reduced, but the ability to adapt to different network configurations and scalability is limited

Engineering Contradiction:
Improvemanufacturing costVSAvoidscalability and network adaptability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic architecture where the controller can reconfigure optical gates in real-time based on network requirements, traffic patterns, and routing decisions. This dynamic reconfigurability allows the node to adapt to different network configurations and scale accordingly, while the base hardware structure remains relatively simple and cost-effective to manufacture

Inventive Principle:
Principle #15Dynamics

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

The solution enhances connectivity and scalability, reduces the number of optical filters, and maintains optical domain functionality similar to electronic routers, improving network adaptability and efficiency.

Implementation Method 1

a respective wavelength channel separator disposed on each of the inputs and capable of separating on separator outputs for packets of optical signals comprising data packets carried by wavelength channels

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

a combiner of wavelength channels respective waves, arranged on said at least one output, this combiner being able to pass to said at least one corresponding output wavelength channels received on at least two inputs of the combiner

Methodology Applied
Scientific EffectOptical multiplexing: Filter (optical)

Implementation Method 3

at least one respective optical gate, arranged on each of said at least two optical insertion paths, and switchable in packet mode to selectively block or pass one or more data packets carried by wavelength channels on said optical insertion paths

Methodology Applied
Scientific EffectOptical switching: Valve

Implementation Method 4

a respective star coupler associated with each respective wavelength channel combiner, said star coupler star having star coupler outputs connected to each insertion optical path associated with the respective combiner

Methodology Applied
Scientific EffectOptical coupling: Waveguide (optics)

Data Source

PatentEP2160045B1Optical packet communication node
Publication Date: 2011.10.12 ALCATEL LUCENT SA
  • EP2160045B1 patent drawingFigure 1
  • EP2160045B1 patent drawingFigure 2
  • EP2160045B1 patent drawingFigure 3

AI summary

The node has a star coupler (46) associated with a combiner (30) i.e. periodic multiplexer, of wavelength channels. Two outputs (50, 53) of the coupler are connected to optical insertion paths (52, 55) associated to the combiner. Third output (132) of the coupler is connected to an extraction module (127) of optical packets. Inputs (102, 109) of the coupler are connected to packet outputs of wavelength channel separators by optical extraction paths e.g. optical fibers. Each separator separates the wavelength channels carrying data packets at a node output on which the combiner is arranged.