Optical Ring Networks with Node-to-Node WDM Channels

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Solution Overview

Problem

Current optical ring networks face challenges in maintaining carrier-grade quality of service due to limitations in protection switching time and capacity upgrade costs, particularly with SONET or RPR rings that require costly O-E-O regenerators at every span, whereas WDM or DWDM rings offer higher capacity and scalability but need optical layer protection within 50 ms.

Innovation Solution

The implementation of optical communication systems with broadcast-and-select WDM signals and node-to-node optical WDM signals that operate without regeneration at each node, utilizing reconfigurable optical add and drop multiplexers (ROADMs) and circulating optical probe signals for fault detection and protection switching, allowing for efficient bandwidth sharing and reduced hardware costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If O-E-O regenerators are used at every span in SONET or RPR rings, then carrier-grade quality of service with protection switching time less than 50 msec is achieved, but network capacity is limited to the capacity of the span with the smallest bandwidth and upgrade costs are high

Engineering Contradiction:

Improveprotection switching timeVSAvoidnetwork capacity

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces O-E-O regenerators with all-optical add/drop nodes that use optical cross-connects and optical switches. This substitution eliminates electrical conversion while maintaining protection switching capability under 50 msec, thereby removing the bandwidth bottleneck and enabling higher network capacity without fork-lifting upgrades

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameter from electrical regeneration to all-optical switching. By using optical cross-connects and optical switches with fast switching capabilities, the system achieves carrier-grade protection switching time while simultaneously enabling higher bandwidth capacity and scalability

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If all-optical add/drop nodes are used in WDM or DWDM rings, then network capacity and scalability are improved with reduced cost, but optical layer protection switching within 50 msec becomes challenging

Engineering Contradiction:

Improvenetwork capacityVSAvoidprotection switching time

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces traditional electronic control mechanisms with all-optical switching using optical cross-connects and optical switches. This substitution enables fast optical layer protection switching within 50 msec while maintaining the high capacity and scalability benefits of all-optical add/drop nodes

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements pre-configured protection paths and fast control mechanisms that enable optical layer protection switching to occur within 50 msec. By having protection paths pre-established and control mechanisms ready, the system achieves both high capacity and carrier-grade reliability

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If fork-lifting upgrade is performed to increase network capacity, then bandwidth is improved, but every span of the ring network must be upgraded which is costly

Engineering Contradiction:

ImprovebandwidthVSAvoidupgrade cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces the fork-lifting upgrade model with independent node upgrades. By using all-optical add/drop nodes with optical cross-connects, each node can be upgraded independently to higher bandwidth capacities without requiring upgrades at every span, thereby dramatically reducing upgrade costs

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8175458B2Optical ring networks having node-to-node optical communication channels for carrying data traffic

Publication Date: 2012.05.08 VELLO SYST

AI summary

Techniques, apparatus and systems for optical communications, including fiber ring networks with protection switching to maintain optical communications when an optical failure occurs and to automatically revert to normal operation when the optical failure is corrected, fiber ring networks that provide a circulating optical probe signal at an optical probe wavelength within the gain spectral range of optical amplifiers used in a fiber ring network to detect an optical failure, and fiber ring networks that support broadcast-and-select optical WDM signals carrying communication traffic to the optical ring nodes without regeneration at each optical ring node and one or more overlaid in-band node-to-node optical signals carrying communication traffic with regeneration at each node.