Reconfigurable Optical Add/Drop Multiplexer Using Coherent Detection

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Solution Overview

Problem

Existing reconfigurable optical add/drop multiplexers have complex structures and high costs due to the need for cascading multiple WSSs or WBs to meet colorless, directionless, and gridless requirements in optical networks, especially in CO-OFDM-based systems, which demand flexible bandwidth management.

Innovation Solution

A reconfigurable optical add/drop multiplexer with a simple structure, utilizing an optical processing unit and coherent detection unit to process and separate optical channels, allowing for adjustable bandwidth and wavelength management, enabling the addition and dropping of optical channels from any direction with any wavelength and bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple WSSs or WBs are cascaded to meet colorless, directionless, and gridless requirements, then the functionality of adding/dropping optical channels is improved, but the device complexity and cost increase

Engineering Contradiction:

Improvecolorless, directionless, and gridless capabilityVSAvoidstructure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the wavelength selection function from complex WSS cascades and implements it through a simplified architecture using optical filters and selective switching. The coherent detection unit separately processes different wavelength channels, eliminating the need for multiple cascaded WSS components while maintaining colorless and directionless functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The optical processing unit is designed to handle multiple wavelength channels simultaneously with a single configuration, providing universal functionality for adding, dropping, and routing channels from any direction. This multi-functional approach replaces the need for multiple specialized WSS components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple WSSs or WBs are cascaded to meet colorless, directionless, and gridless requirements, then the functionality of adding/dropping optical channels is improved, but the cost increases

Engineering Contradiction:

Improvecolorless, directionless, and gridless capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent employs cost-effective optical filters and standard coherent detection components instead of expensive WSS devices. By using more affordable components that can be mass-produced, the overall system cost is reduced while maintaining the required adaptability for colorless, directionless, and gridless operations.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Quantity of substance

If traditional OADM structure is used, then the bandwidth construction is sufficient, but the bandwidth management flexibility is insufficient

Engineering Contradiction:

Improvebandwidth capacityVSAvoidbandwidth management flexibility

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic bandwidth management through software-controlled coherent detection and optical processing. The system can dynamically adjust which wavelength channels are added or dropped, and can flexibly allocate bandwidth resources based on real-time network demands, transforming static OADM functionality into a dynamic, reconfigurable system.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system enables flexible bandwidth management by changing operational parameters such as wavelength selection, channel allocation, and detection settings through software control. This allows the same physical infrastructure to adapt to varying bandwidth requirements without hardware reconfiguration.

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 flexible and efficient bandwidth management, meeting colorless, directionless, and gridless requirements, reducing complexity and cost while enabling flexible optical network configurations.

Implementation Method 1

a coherent detection unit for performing a coherent detection on the second optical signal so as to separate from the second optical signal an optical channel contained therein

Methodology Applied

Scientific EffectCoherent detection: Homodyne Detection

Data Source

PatentUS8861967B2Reconfigurable optical add/drop multiplexer and reconfigurable optical add/drop multiplexing method

Publication Date: 2014.10.14 WUHAN POST & TELECOMM RES INST CO LTD

AI summary

A reconfigurable optical add/drop multiplexer and a reconfigurable optical add/drop multiplexing method are provided. The reconfigurable optical add/drop multiplexer comprises: an optical processing unit for receiving a first optical signal containing a plurality of optical channels, processing the first optical signal to generate a second optical signal which is a part of the first optical signal, and outputting the second optical signal; and a coherent detection unit for performing a coherent detection on the second optical signal so as to separate from the second optical signal an optical channel contained therein, and outputting the optical channel. With the reconfigurable optical add/drop multiplexer and the reconfigurable optical add/drop multiplexing method, any number of degrees can be supported, and adding/dropping of an optical channel with any wavelength and any bandwidth to/from any direction can be achieved, so that requirements of being colorless, directionless, contentionless and gridless can be satisfied.