Hybrid Optical Ring Network with ROADM and Passive Splitters
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Solution Overview
Problem
Current optical transmission networks face limitations in flexibility, capacity utilization, and complexity, particularly in handling fiber breaks and changing traffic forecasts, with existing solutions requiring significant operational effort and resource allocation for rerouting and interface duplication.
Innovation Solution
A hybrid optical transmission network with a closed ring structure combining passive optical splitters and couplers with reconfigurable optical add/drop multiplexers (ROADM) and fast optical switches, allowing automatic self-healing and maximizing interface capacity utilization without network management system integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed optical add/drop nodes (FOADM) are used in aggregation networks, then wavelength utilization is economical and spectral separation avoids blockages, but flexibility to change traffic forecasts is limited and interface capacity is constrained to 50% for protection
Solution Approach 1:
The patent applies dynamics by replacing fixed FOADM configurations with dynamic reconfigurable optical add/drop multiplexers (ROADMs) that can dynamically adjust wavelength routing and traffic distribution. This enables the network to adapt to changing traffic forecasts while maintaining protection capabilities through dynamic path selection rather than static 50% capacity constraints
Solution Approach 2:
The patent changes the operational parameters of optical network elements from fixed capacity allocation to flexible wavelength-selective switching. By enabling ROADMs to dynamically reconfigure which wavelengths are added, dropped, or passed through, the system can optimize capacity utilization according to actual traffic conditions while maintaining protection against fiber breaks
2Reliability
If redundant interfaces are deployed for backbone node failure protection, then reliability is improved, but cost and device complexity increase significantly
Solution Approach 1:
The patent implements self-service protection mechanisms where the optical network elements automatically detect failures and reroute traffic without requiring manual intervention or pre-configured redundant interfaces at every node. The ROADMs dynamically reconfigure their wavelength routing based on detected failures, providing protection while reducing the need for duplicate interfaces
Solution Approach 2:
The system employs feedback mechanisms where optical network elements continuously monitor the status of fiber connections and backbone nodes. When a failure is detected, the system receives feedback and automatically adjusts the routing configuration of ROADMs to redirect traffic through alternative paths, eliminating the need for static redundant interface deployment
3Reliability
If IP layer rerouting is used for connection restoration after fiber break, then protection is achieved, but operational effort and cost increase significantly
Solution Approach 1:
The patent replaces the mechanical/IP-layer rerouting process with an optical-layer solution. Instead of relying on IP routing protocols to detect and restore connections after fiber breaks, the system uses optical network elements with automatic failover capability that restore connectivity at the optical layer, significantly reducing operational effort and restoration time
4Device complexity
If passive optical splitter/coupler technology is used, then network management complexity is reduced and flexibility for future transmission rates is improved, but optical signal loss increases requiring amplifiers
Solution Approach 1:
The patent introduces optical amplifiers as intermediary devices between the passive splitter/coupler elements and the ROADMs. These amplifiers compensate for the signal loss introduced by the passive optical components, enabling the network to benefit from simplified management and future-proof architecture while maintaining adequate signal levels for operation
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 enables efficient and flexible optical layer protection, achieving 100% interface capacity utilization and reducing operational complexity, with fast switching times that meet high-priority service level agreements and support future transmission rates without rigid filtering constraints.
Implementation Method 1
couple an optical wavelength-division multiplexed signal into both optical signal paths using passive optical couplers
Implementation Method 2
extract an optical wavelength-division multiplexed signal from each of the two signal paths on the ring using passive optical splitters
Implementation Method 3
The optical transmission network comprises at least one first optical network element... configured to simultaneously couple an optical wavelength-division multiplexed signal into both optical signal paths
Data Source
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AI summary
The invention proposes a hybrid optical transmission network (20, 30) for transmitting optical signals in wavelength-division multiplexing operation with a plurality of optical network elements (401-405, 510, 520, 530) arranged as a ring network, which comprises first and second optical network elements (401-405, 510, 520, 530), wherein the first optical network elements comprise, in particular, passive optical dividers and couplers, and the second optical network elements are configured as ROADM, and wherein the optical network elements are further configured to each extract an optical wavelength-division multiplex signal from a first and a second optical signal path of the optical transmission network that is counter-rotating to the first, and to automatically select one of the extracted optical signals for further processing, and the second optical network elements (510, 520, 530) are configured such thatthat the first and second signal paths are interrupted for each transmission wavelength used in at least one of the second optical network elements (510, 520, 530). Furthermore, the invention provides optical network elements for use in such an optical transmission network.