Flexible ROADM Power Setpoints for C+L Loading Transients
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Solution Overview
Problem
C+L optical line systems experience optical power transients during loading operations due to Stimulated Raman Scattering (SRS) effect, leading to traffic drop and requiring lengthy automatic gain control (AGC) cycles, which disrupt downstream segments and impact system performance.
Innovation Solution
Implementing a Service and Power Control Orchestrator (SPCO) for network-wide orchestration and coordination of optical power control, using a network element with a processor, flexible ROADM module, and control blocks to pause and adjust optical power set points during network state changes, minimizing power excursions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If automatic gain control (AGC) cycles are run to correct power transients, then power stability is improved, but system downtime increases and productivity decreases
Solution Approach 1:
The system performs preliminary action by predicting impending network state changes (such as service activation or deactivation) before they occur. When a state change is anticipated, the system proactively adjusts power setpoints at affected network elements and notifies downstream elements to prepare, thereby preventing power transients before they disrupt traffic flow. This eliminates the need for corrective AGC cycles that would otherwise be required after the state change occurs.
Solution Approach 2:
The system implements beforehand cushioning by establishing a buffer mechanism through power setpoint adjustments prior to network state changes. Downstream network elements are notified in advance and adjust their power settings to compensate for upcoming changes, creating a protective cushion that prevents power excursions from propagating through the network. This cushioning effect maintains power stability without requiring lengthy corrective AGC cycles.
2Manufacturing precision
If sequential operations are performed on network segments, then power control precision is improved, but operation time increases and productivity decreases
Solution Approach 1:
The system performs preliminary action by identifying all network elements affected by an impending state change and pre-adjusting their power setpoints before the state change occurs. This includes notifying downstream elements in advance so they can prepare their power settings. By performing these adjustments preliminarily, the system achieves precise power control across multiple segments simultaneously rather than sequentially, significantly reducing the time required for operations.
3Adaptability or versatility
If power adjustments are made during network state changes, then adaptability is improved, but power transients increase and reliability worsens
Solution Approach 1:
The system performs preliminary action by detecting impending network state changes and proactively adjusting power setpoints at affected network elements before the state change occurs. Downstream elements are notified in advance and prepare their power settings accordingly. This preliminary coordination ensures that power adjustments are made in a controlled manner that maintains traffic continuity, rather than making reactive adjustments that would cause harmful transients.
Solution Approach 2:
The system implements feedback mechanisms where downstream network elements are notified of impending state changes and provide status information about their power settings. The orchestrating element monitors these feedback signals and coordinates power adjustments across the network to maintain stability. This feedback loop enables the system to adapt to network state changes while preventing power transients that would disrupt traffic.
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
The SPCO effectively mitigates optical power transients by coordinating power adjustments across the network, reducing the need for sequential AGC cycles and enhancing system performance by minimizing downtime and power excursions.
Implementation Method 1
optical amplifiers, a light source such as lasers or LEDs
Implementation Method 2
C+L optical line systems may be susceptible to experiencing optical power transients during loading operations due to Stimulated Raman Scattering (SRS) effect across the different frequency bands
Data Source
AI summary
Disclosed herein are methods and systems for correcting power excursions. One exemplary network element may be provided with a processor; a first line port; a flexible ROADM module including a wavelength selective switch, a multiplexer, and one or more control block; a second line port; and a memory storing an orchestrator application and processor-executable instructions. Responsive to receiving a first signal indicative of an impending network state change, the processor-executable instructions cause the processor to pause all power adjustments by the control block on the flexible ROADM module and save at least one power set point value for each active passband from a first optical signal multiplexed into a second optical signal; and responsive to receiving a second signal indicative of the network state change, adjust an optical power of each active passband from the first optical signal multiplexed into the second optical signal using the power set point values.