Optical Network Element Loopback Path Testing
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Solution Overview
Problem
Monitoring the functionality of components in add and drop modules of optical network elements is challenging, especially when these components are not actively used, leading to difficulties in detecting failures and maintaining network integrity.
Innovation Solution
The implementation of an optical loop back path that connects the add module to the drop module, allowing for the generation and transmission of optical signals for testing purposes, enabling the simultaneous testing of wavelength multiplexing and demultiplexing arrangements, as well as continuous alarm surveillance without requiring permanent probing signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical components are not actively used in add and drop modules, then network resources are optimized, but monitoring and detection of component failures become difficult
Solution Approach 1:
The patent implements preliminary action by pre-configuring optical loopback paths and test signal generation capabilities within the add and drop modules. Test signals are prepared and routed through optical loopback paths before actual network operations, enabling proactive component monitoring without interfering with normal network traffic. This allows components to be monitored in advance even when not actively transmitting network signals.
Solution Approach 2:
The patent introduces an intermediary test signal as a mediator between the optical components and monitoring systems. This test signal travels through the optical loopback path, interacting with components under test and returning to the monitoring system. The intermediary signal enables indirect observation of component status without requiring direct access to the components themselves, solving the monitoring difficulty when components are inactive.
2Reliability
If permanent probing signals are used for continuous monitoring, then component reliability is improved, but network bandwidth and resources are consumed
Solution Approach 1:
The patent implements periodic action by sending test signals at intervals rather than continuously. The optical test signals are generated periodically through the add module, circulated via optical loopback paths, and received by the drop module at scheduled times. This periodic testing maintains component monitoring capability while significantly reducing network resource consumption compared to continuous probing signals.
Solution Approach 2:
The patent applies partial action by implementing monitoring only when necessary - specifically when components are inactive or during scheduled maintenance windows. Instead of continuously monitoring all components at all times, the system selectively activates test signals based on operational conditions, reducing overall resource consumption while maintaining adequate reliability coverage.
3Difficulty of detecting and measuring
If optical loopback path is implemented for testing, then component testing capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the testing function with existing optical infrastructure by integrating optical loopback paths into the standard add and drop module architecture. The same optical components used for network operations (optical switches, couplers, waveguides) are utilized for testing purposes as well. This merging eliminates the need for separate dedicated testing infrastructure, reducing overall device complexity while improving testing capability.
Solution Approach 2:
The patent implements universality by designing optical components that serve multiple functions - the optical loopback paths and test signal routing infrastructure are used both for network operations and for component testing. The same optical switches and couplers that route network traffic also route test signals, making the system multi-functional and reducing the need for additional dedicated testing 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
This solution allows for the effective monitoring of unused components, ensuring timely detection of failures and maintaining network reliability by enabling simultaneous testing of multiple transmitters and receivers, and continuous alarm surveillance, even when components are not involved in network services.
Implementation Method 1
an add module comprising a wavelength multiplexing arrangement connected to the optical add path and a plurality of optical transmitters connected to the wavelength multiplexing arrangement for generating optical signals on the wavelength channels
Implementation Method 2
a drop module comprising a plurality of optical receivers for demodulating optical signals
Data Source
Figure 1~3
AI summary
An optical network element comprises: an optical input (10), a distributing component (14) arranged to pass optical signals from the optical input to an optical transit path (16) and to an optical drop path (23), a drop module (20) comprising a wavelength demultiplexing arrangement (22) connected to the optical drop path (23) and a plurality of optical receivers (21) for demodulating optical signals, an add module (30) comprising a wavelength multiplexing arrangement (32) connected to an optical add path (33) and a plurality of optical transmitters (31), and an optical loop back path (140) connecting the add module to the drop module for passing optical signals generated by the transmitters of the add module to the receivers of the drop module for the purpose of testing. Application to testing of transmitters, receivers and the optical add and drop modules of an optical network element and to maintaining accurate alarm surveillance.