Optical Add-Drop Device Using Spatial Switching Matrix and AWG

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Solution Overview

Problem

Current optical add and drop devices in WDM networks lack flexibility, scalability, and efficiency, particularly in transparent wavelength switching nodes, where they are limited in generating optical paths between arbitrary ports and suffer from high loss and complexity.

Innovation Solution

The implementation of an optical add or drop device using a transponder block with an optical spatial switching matrix and an arrayed waveguide grating, enabling the generation of transparent optical paths between any transponder-side and AWG-side ports, along with programmable demultiplexers and multiplexers for multidirectional and contentionless operations, and the use of MEMS technology for flexible configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If discrete components are used to construct wavelength switching nodes, then device flexibility and configurability are improved, but device complexity and size increase

Engineering Contradiction:
Improvedevice flexibilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple discrete optical components (switches, multiplexers, demultiplexers) into a single integrated Wavelength Selective Switch (WSS) module. This integration maintains the functional flexibility of discrete components while reducing overall device complexity and size, as the WSS provides both wavelength selection and switching functions in one unit.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The WSS module serves multiple functions simultaneously: it acts as a wavelength demultiplexer, a wavelength selector, and an optical switch. This multi-functionality eliminates the need for separate discrete components for each function, thereby reducing device complexity while maintaining adaptability.

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

2Ease of operation

If optical-electrical-optical conversions are performed at network routing nodes, then signal processing capability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvesignal processing capabilityVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the optical processing functions from the network routing nodes and places them at the edge devices (transponders). This allows the core network nodes to operate purely in the optical domain using WSS modules, eliminating the need for optical-electrical-optical conversions at routing nodes while maintaining signal processing capability at the edges.

Inventive Principle:
Principle #2Taking out (Extraction)

3Quantity of substance

If separate switch modules are used for each wavelength, then wavelength channel capacity is improved, but device complexity and size increase

Engineering Contradiction:
Improvewavelength channel capacityVSAvoiddevice complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

Instead of using separate physical switch modules for each wavelength, the patent combines all wavelength handling capabilities into a single WSS module that can dynamically select and route any wavelength channel. This integration maintains full wavelength channel capacity while significantly reducing device complexity compared to having dedicated modules for each wavelength.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If optical branching/coupling devices are used in optical switch networks, then signal distribution capability is improved, but signal loss increases

Engineering Contradiction:
Improvesignal distribution capabilityVSAvoidsignal loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent replaces traditional optical branching/coupling devices with a WSS-based switching mechanism that uses wavelength-selective reflection and routing. This substitution eliminates the inherent signal loss associated with optical couplers by using high-efficiency wavelength-selective switches that can route signals with minimal insertion loss.

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

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 provides flexible, scalable, and low-loss optical path generation, enabling efficient multidirectional and contentionless operations, suitable for high-data-rate signals with reduced physical signal impact and cost-efficiency, supporting pay-as-you-grow deployment.

Implementation Method 1

an arrayed waveguide grating, the arrayed waveguide grating comprising a plurality of network-side ports, each connected to a respective one of the WDM links, and a plurality of matrix-side ports

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

an optical spatial switching matrix comprising a plurality of transponder-side ports connected to the transponders and a plurality of AWG-side ports, wherein the optical spatial switching matrix is adapted to produce a plurality of optical paths as a function of a configuration state

Methodology Applied
Scientific EffectOptical switching:

Implementation Method 3

a plurality of WDM links each adapted to carry optical signals on a plurality of wavelength channels

Methodology Applied
Scientific EffectWavelength division multiplexing:

Data Source

PatentEP2426841B1Optical add and/or drop device for an optical network element
Publication Date: 2019.01.09 ALCATEL LUCENT SA
  • EP2426841B1 patent drawingFigure 1~3
  • EP2426841B1 patent drawingFigure 4~5
  • EP2426841B1 patent drawingFigure 6~7

AI summary

An optical add and/or drop device (30, 40) comprises a plurality of WDM links (31, 41) and a transponder block (33, 43), the transponder block comprising: a plurality of transponders (1, 8) each adapted to generate or receive an optical signal on a selected wavelength channel, an optical spatial switching matrix (3) comprising a plurality of transponder-side ports (4) connected to the transponders and a plurality of AWG-side ports (5), and an arrayed waveguide grating (6), the arrayed waveguide grating comprising a plurality of network-side ports, each connected to a respective one of the WDM links (31,41), and a plurality of matrix-side ports, each connected to a respective one of the AWG-side ports of the optical spatial switching matrix, wherein a passband of the arrayed waveguide grating between a network-side port and a matrix-side port is dependent upon a rank of the network-side port and a rank of the matrix-side port.