ROADM Transmit Power Equalization via Optical Controller
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Solution Overview
Problem
In optical communication networks, reconfigurable optical add-drop multiplexers (ROADMs) face challenges in compensating for changes in optical powers when new services are turned up or down, leading to frequent signal regeneration and increased costs due to the inability to communicate optical control information between nodes in open networks.
Innovation Solution
An optical controller is used to identify and equalize the transmit power of in-service channels in ROADMs by obtaining optical power targets, transitioning channels to a power mode, and adjusting their transmit power based on these targets, allowing for independent operation in steady state mode without software-defined networking (SDN) computing module instructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ROADMs are implemented in an open optical network without optical control information communication, then device complexity is reduced, but optical power compensation capability deteriorates leading to frequent signal regeneration
Solution Approach 1:
The ROADM node autonomously monitors its own optical power levels and performs self-compensation through local gain adjustment mechanisms, eliminating the need for complex inter-node control communication while maintaining reliable optical power compensation
Solution Approach 2:
The system implements local optical power feedback loops where each ROADM node continuously monitors its output power levels and automatically adjusts its gain settings to compensate for power variations, ensuring stable operation without external control signals
2Manufacturing precision
If transmit power is adjusted for each in-service channel to achieve equalization, then optical power distribution uniformity is improved, but control system complexity increases
Solution Approach 1:
The system achieves power equalization by dynamically adjusting the gain parameter of existing in-service channels rather than modifying the physical structure or adding complex control hardware, simplifying the control system while improving power distribution uniformity
Solution Approach 2:
The controller pre-calculates the required gain adjustments for each channel based on target power levels and applies these adjustments in a coordinated manner, achieving precise power equalization without requiring complex real-time control algorithms
Data Source
AI summary
An optical system including a ROADM including previously in-service channels; a SDN computing module in communication with the ROADM over a DCN, the SDN computing module providing an instruction to place in-service an additional channel at the ROADM; an optical controller included by the ROADM and configured to, in response to the instruction to place in-service the additional channel at the ROADM: obtain optical power targets for each in-service channel including the previously in-service channels and the additional in-service channel; equalize a transmit power for each in-service channel of the ROADM, including: identify the transmit power of each in-service channel; transition each in-service channel to a power mode; adjust the transmit power of each in-service channel based on, for each in-service channel, the optical power target for the in-service channel and the identified transmit power for the in-service channel; and transition each in-service channel to a steady state mode.