DWDM Line Card Using Optical-Electrical Conversion

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Solution Overview

Problem

Traditional DWDM networks face challenges in simplicity, flexibility, robustness, and bandwidth utilization efficiency, particularly with the use of EDFAs and ROADM, which are costly and complex, making it difficult to support dynamic wavelength demands and network scalability.

Innovation Solution

A low-cost multi-channel DWDM line card system based on monolithically/hybrid integrated DWDM transmitter/receiver arrays, which includes a photonic integrated device, clock and data recovery device, and a switch, eliminating the need for optical power management and reducing the number of FEC chips, allowing for scalable and reconfigurable networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional DWDM networks use EDFAs and ROADM, then bandwidth utilization and signal transmission are improved, but device complexity and operating expenses increase

Engineering Contradiction:
Improvesignal transmissionVSAvoidnetwork complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the EDFA component from the traditional DWDM network architecture by replacing it with a regenerator-based system. The regenerator converts optical signals to electrical signals, processes them through FEC, and reconverts them to optical signals, thereby removing the need for complex optical power management while maintaining signal transmission reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The regenerator device performs multiple functions simultaneously: signal regeneration, FEC encoding/decoding, wavelength conversion, and optical-to-electrical and electrical-to-optical conversion. This multi-functionality replaces the separate functions previously handled by EDFAs and ROADM components, simplifying the overall network architecture.

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

2Adaptability or versatility

If ROADM is used for dynamic wavelength provisioning, then network flexibility is improved, but operational complexity and cost increase

Engineering Contradiction:
Improvewavelength provisioning flexibilityVSAvoidoperation complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent replaces the optical-domain ROADM mechanism with an electrical-domain switching approach. The regenerator converts optical signals to electrical signals, allowing standard electrical switches to route wavelengths, thereby eliminating the need for complex optical switching mechanisms and reducing operational complexity.

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

Solution Approach 2:

The regenerator acts as an intermediary device that bridges optical and electrical domains. By converting optical signals to electrical signals for processing and switching, and then converting back to optical signals, it simplifies the wavelength provisioning process while maintaining network flexibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If integrated DWDM transmitter/receiver arrays are used, then network simplicity and robustness are improved, but capital cost increases

Engineering Contradiction:
Improvenetwork simplicityVSAvoidcapital cost
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The patent segments the regenerator function into separate functional modules: optical-to-electrical conversion, electrical signal processing (including FEC), and electrical-to-optical conversion. This segmentation allows for more cost-effective implementation using standard components rather than expensive integrated arrays.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the operating parameters and architecture from monolithic integrated DWDM arrays to a distributed modular approach using standard electrical components. This parameter change in the system architecture significantly reduces capital costs while maintaining network simplicity and robustness.

Inventive Principle:
Principle #35Parameter changes

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 supports larger networks with lower operating expenses, simplifies network engineering, and reduces capital costs while maintaining high performance, scalability, and flexibility, with localized optical and electrical impairments that are linearly added rather than exponentially, enabling long-reach communications with limited error rates.

Implementation Method 1

a first photonic integrated device configured to receive a first optical signal and output a first plurality of electrical signals for a first plurality of channels respectively

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

a first clock and data recovery device configured to receive the first plurality of electric signals and retime the first plurality of electric signals

Methodology Applied
Scientific EffectClock recovery and retiming:

Implementation Method 3

a first switch coupled to the first clock and data recovery device, a first interface, and a second interface

Methodology Applied
Scientific EffectElectrical switching:

Data Source

PatentEP2127158B1Method and apparatus for DWDM line card
Publication Date: 2013.07.03 HUAWEI TECH CO LTD
  • EP2127158B1 patent drawingFigure 1
  • EP2127158B1 patent drawingFigure 2
  • EP2127158B1 patent drawingFigure 3

AI summary

A system and method for multiple-channel line card. The system includes a first photonic integrated device configured to receive a first optical signal and output a first plurality of electrical signals for a first plurality of channels respectively. The first plurality of channels corresponds to a first plurality of wavelength ranges associated with the first optical signal. Additionally, the system includes a first clock and recovery device configured to receive the first plurality of electric signals and retime the first plurality of electric signals, and a first switch coupled to the first clock and recovery device, a first interface, and a second interface. Moreover, the system includes the first interface configured to output a second plurality of electrical signals to another system for multiple-channel line card, and the second interface configured to couple with one or more plugged first channel devices.