Optical Transceiver Automatic Power Adjustment via Supervisory Channel
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Solution Overview
Problem
In wavelength division multiplexing (WDM) optical networks, especially with fixed optical add/drop multiplexing (FOADM) nodes, balancing optical power levels across all wavelengths is challenging due to varying transmit powers and different loss levels of filters, requiring cumbersome manual adjustments.
Innovation Solution
An automatic power adjustment method and apparatus that uses optical pilot signals to determine span loss and adjust signal power levels automatically, ensuring a predetermined receive signal power level at far-end devices, employing variable optical attenuators or amplifiers and embedded or out-of-band communication channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual power adjustment using fixed attenuators and power meters is used, then optical power levels can be adjusted, but the procedure is very cumbersome and time consuming
Solution Approach 1:
The system performs self-diagnosis and self-adjustment by automatically measuring optical power levels through the optical supervisory channel and adjusting attenuator settings without requiring manual intervention with power meters and spectrum analyzers
Solution Approach 2:
The system uses feedback from optical power measurements transmitted through the optical supervisory channel to automatically adjust attenuator settings, creating a closed-loop control system that continuously monitors and corrects power imbalances
2Productivity
If fixed OADM filters are used for wavelength multiplexing, then data transmission capacity is increased, but power balancing becomes challenging due to varying transmit powers and different filter losses
Solution Approach 1:
The optical supervisory channel acts as an intermediary carrier that transports power level measurement information between nodes, enabling automatic power balancing without adding complexity to the data transmission path
Solution Approach 2:
The system dynamically changes attenuator settings based on measured power levels to compensate for varying filter losses and transmit power differences across wavelengths, maintaining balanced optical power distribution
Data Source
Figure 1A~1B
Figure 2
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AI summary
A method and apparatus for performing an automatic power adjustment wherein a signal power level of an optical signal transmitted by an optical transceiver via an optical span to a far-end device is adjusted automatically in response to a determined span loss of the optical span to achieve a predetermined desired receive signal power level of the optical signal at the far-end device.