Optical Amplifier Mode Switching to Prevent Power Oscillations
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Solution Overview
Problem
Optical power oscillations occur in optical amplifier chains when switching from a constant gain 'open loop' mode to a variable gain 'closed loop' mode, leading to potential disruptions in network traffic due to gain control errors and transient power changes.
Innovation Solution
Configuring optical amplifiers in an optical amplifier chain to switch from a constant gain 'open loop' mode to a variable gain 'closed loop' mode after a unique time period, which can be a preselected time plus an additional time period proportional to their position in the chain, to ensure steady-state operation and prevent power oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If optical amplifiers switch from open loop to closed loop mode simultaneously, then the system returns to normal operation faster, but optical power oscillations occur causing network disruptions
Solution Approach 1:
The patent segments the simultaneous mode switching operation into sequential switching for each optical amplifier in the chain. Each amplifier switches from open loop to closed loop mode at different time instances, preventing the synchronized feedback that causes oscillations while still achieving relatively fast restoration of normal operation.
Solution Approach 2:
The patent applies preliminary action by having optical amplifiers switch to closed loop mode in a predetermined sequential order after the transient event has settled. This preliminary sequencing of operations prevents oscillations from occurring while maintaining efficient system recovery.
2Stability of the object's composition
If optical amplifiers are kept in open loop freeze condition, then optical power transients are managed and channel stability is maintained, but the system cannot adapt to current channel conditions
Solution Approach 1:
The patent implements a dynamic operating mode strategy where optical amplifiers can switch between open loop freeze condition and closed loop variable gain condition. The system dynamically adapts to channel conditions by selecting the appropriate mode: open loop during transients for stability, and closed loop during steady state for adaptability to current channel configurations.
Solution Approach 2:
The patent changes the operational parameters of optical amplifiers by switching between two distinct gain control modes. The system changes from constant gain (open loop) to variable gain (closed loop) based on the operational state, allowing the amplifiers to maintain stability during transients while adapting to current channel conditions when stable.
3Loss of time
If optical amplifiers switch mode immediately after transient, then system recovery is faster, but gain control errors cause power oscillations
Solution Approach 1:
The patent applies preliminary action by waiting for the transient event to settle before initiating the sequential mode switching process. This preliminary delay ensures that gain control accuracy is maintained while still achieving relatively fast system recovery through automated sequential switching.
Solution Approach 2:
The patent uses feedback mechanisms in the closed loop mode to detect and correct gain control errors. By switching to closed loop mode sequentially after transients settle, the feedback control can accurately maintain target optical power levels without the oscillations that would occur with immediate simultaneous switching.
Data Source
AI summary
A method (10) of changing operating mode of an optical amplifier in an amplifier chain in an optical network, the optical amplifier initially configured to operate in a first mode to apply a substantially constant first gain to an optical signal comprising a plurality of optical channels, the method comprising, after a time period unique to the optical amplifier within the amplifier chain (12), configuring the optical amplifier to operate in a second mode to apply a second gain to the optical signal so that the optical power of the optical signal is maintained at a target optical power dependent on a current plurality of optical channels in the optical signal (14).