Resilient Add-Drop Module for Optical Ring Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Converged optical networks face high costs and complexity due to the need for reconfigurable optical add/drop multiplexers (ROADMs) to efficiently route wavelength channels, making it costly to transport multiple services optically, and packet aggregation becomes inefficient with significant traffic increases.
Innovation Solution
A resilient add-drop module with a dual-arm passive optical filter and a cyclic arrayed waveguide grating (AWG) that passively drops and adds wavelength channels within a fixed band, providing 1+1 resilience against fiber and node failures, reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ROADMs are used to provide flexible routing capability and resilience, then routing flexibility and reliability are improved, but device complexity and cost increase significantly
Solution Approach 1:
The system segments the optical network into multiple access subnetwork rings, each independently managed with its own add-drop module. This segmentation allows resilience to be achieved at the ring level without requiring complex reconfigurable components at every node, as failures are contained and managed within individual ring segments.
Solution Approach 2:
Instead of using active reconfigurable components (ROADMs) to achieve resilience, the invention inverts the approach by using passive optical filters with fixed wavelength assignments. The resilience is achieved through the passive dual-arm architecture that automatically routes traffic around failures without requiring active control or reconfiguration at each node.
2Adaptability or versatility
If ROADMs are deployed to enable selective addition and dropping of wavelength channels, then adaptability is improved, but manufacturing cost increases
Solution Approach 1:
The invention extracts the reconfigurable functionality from individual network nodes and consolidates it at the ring level through centralized control. Each node uses a simple passive add-drop module with fixed wavelength assignments, removing the need for expensive reconfigurable components at each location while maintaining overall network flexibility through the cyclic ring architecture.
Solution Approach 2:
The system replaces expensive ROADMs with inexpensive passive optical filters and fixed AWGs at each node. These passive components are much cheaper to manufacture and deploy, and while they lack individual reconfigurability, the overall network maintains adaptability through the centralized control plane that can reassign wavelengths across the ring.
3Ease of manufacture
If packet aggregation is used to converge multiple services, then device cost is reduced, but productivity and efficiency decrease with traffic increases
Solution Approach 1:
The invention substitutes optical-layer service convergence (using separate wavelength channels for different services) for packet-layer convergence. This optical convergence using passive WDM technology is more efficient and scalable than packet aggregation, as it avoids the processing overhead and complexity of packet switching while maintaining the ability to handle multiple services simultaneously with simple passive components.
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 reduces the complexity and cost of optical network nodes while maintaining resilience, enabling efficient optical convergence of multiple services by using a dual-arm passive optical filter and cyclic AWG, which minimizes module variants and operational costs.
Implementation Method 1
a dual-arm passive optical filter configured to resiliently drop any wavelength channels within a fixed band uniquely allocated to the access subnetwork node from either arm of the access subnetwork ring
Implementation Method 2
the cyclic AWG is configured to demultiplex wavelength channels dropped by the dual-arm filter
Implementation Method 3
the cyclic AWG is configured to multiplex wavelength channels to be added by the dual-arm filter
Data Source
AI summary
Embodiments herein include a resilient add-drop module for use in one of multiple access subnetwork nodes forming an access subnetwork ring. The module comprises a dual-arm passive optical filter and a cyclic arrayed waveguide grating (AWG). The dual-arm passive optical filter is configured to resiliently drop any wavelength channels within a fixed band uniquely allocated to the access subnetwork node from either arm of the access subnetwork ring and to resiliently add any wavelength channels within the fixed band to both arms of the access subnetwork ring. The cyclic AWG is correspondingly configured to demultiplex wavelength channels dropped by the dual-arm filter and to multiplex wavelength channels to be added by the dual-arm filter. Configured in this way, the module in at least some embodiments advantageously reduces the complexity and accompanying cost of nodes in an optical network, while also providing resilience against fiber and node failures.