Optical Add/Drop Multiplexer With Redundant Wavelength Failover
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Solution Overview
Problem
Existing ROADM devices in optical submarine cable systems fail to maintain stable communication and transmission quality when abnormalities occur in wavelength selective switches, such as changes in wavelength characteristics or component aging, leading to potential communication failures.
Innovation Solution
An optical add/drop multiplexer equipped with a first and second wavelength selection means, where the second selection means takes over when the first encounters an abnormality, and includes a measurement means to monitor and maintain optical power, ensuring continuous operation and stable transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single wavelength selective switch is used in the ROADM device, then the device complexity is reduced, but the reliability deteriorates because stable transmission characteristics cannot be maintained when abnormalities occur
Solution Approach 1:
The wavelength selection function is segmented into multiple independent wavelength selective switches (first WSS 11, second WSS 12, third WSS 13) that can operate independently. This segmentation allows the system to maintain functionality even when one switch experiences abnormalities, as other switches can continue to route wavelengths correctly.
Solution Approach 2:
The patent implements beforehand cushioning by providing redundant wavelength selective switches and monitoring their characteristics in advance. When abnormalities are detected through wavelength characteristic measurement, the system can switch to backup switches before complete failure occurs, ensuring continuous stable transmission.
2Reliability
If redundant wavelength selection means are added to maintain stability, then the reliability improves, but the device complexity increases
Solution Approach 1:
The wavelength selective switches are designed with multi-functionality, serving both as primary routing components and as backup units. Each switch can perform wavelength selection and path routing functions, allowing any switch to potentially replace another in case of failure, thereby reducing the need for completely separate redundant systems.
Solution Approach 2:
The patent implements feedback mechanisms through wavelength characteristic measurement units that continuously monitor the performance of each wavelength selective switch. This feedback allows the control unit to detect abnormalities early and automatically switch to alternative switches, maintaining reliable operation without requiring complex manual intervention or over-engineered redundant systems.
3Measurement precision
If wavelength characteristics are monitored continuously, then the transmission quality is maintained, but the device complexity and measurement requirements increase
Solution Approach 1:
The system performs preliminary wavelength characteristic measurements during the initialization phase and at scheduled intervals, rather than requiring continuous real-time monitoring. This preliminary action approach allows the system to establish baseline characteristics and detect significant deviations without the complexity of continuous high-frequency measurement systems.
Data Source
AI summary
An optical add/drop multiplexer includes: a first wavelength selector configured to output an optical signal of each wavelength of an inputted first wavelength multiplexed signal while selecting a path for each wavelength; a measurement circuit configured to measure optical power of an inputted optical signal; and a second wavelength selector including a circuit configured to output an optical signal of each wavelength of the first wavelength multiplexed signal while selecting a path for each wavelength, in place of the first wavelength selector when an abnormality occurs in the first wavelength selector, and a circuit configured to output an inputted second wavelength multiplexed signal for each prescribed wavelength unit to the measurement circuit when the first wavelength selector normally operates.