Modular Optical Node ASE Loading for C+L Band Upgrade
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Solution Overview
Problem
Conventional optical networking systems face challenges in modular deployment and upgrade of multiple optical spectrum bands (C and L bands) due to performance shifts caused by Stimulated Raman Scattering (SRS), requiring complex adjustments and calibration of Raman gain, especially when adding L-Band hardware, which has not been widely deployed.
Innovation Solution
The implementation of coordinated Amplified Spontaneous Emission (ASE) loading across both C and L bands, using modular hardware design with ASE noise sources to provide channelized and bulk ASE loading, allowing for initial deployment without full L-Band hardware, and enabling seamless transition to L-Band upgrade with channelized ASE loading, calibrated Raman gain, and simplified control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If L-Band hardware is added to extend optical spectrum usage, then fiber capacity is doubled, but performance shifts occur in existing C-Band channels due to Stimulated Raman Scattering
Solution Approach 1:
The patent applies preliminary action by deploying ASE noise sources in advance to load the L-Band spectrum before actual L-Band signals are transmitted. This pre-loading creates a controlled noise environment that allows the system to adapt to the presence of L-Band energy, thereby preventing performance shifts in C-Band channels when full L-Band operation begins. The noise sources are configured to simulate the spectral energy distribution of future L-Band signals.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the power levels and spectral characteristics of ASE noise sources to match the expected L-Band signal parameters. By varying the noise loading parameters (power, spectral shape, bandwidth) to correspond with planned L-Band operating conditions, the system pre-adapts to the parameter changes that will occur when L-Band hardware is fully activated, thus maintaining C-Band channel stability.
2Ease of manufacture
If L-Band hardware is added later, then initial deployment cost is reduced, but complex adjustments and calibration are required during upgrade
Solution Approach 1:
The patent applies preliminary action by performing calibration and adaptation during the initial deployment phase using ASE noise sources, rather than during the upgrade phase. The system is pre-calibrated to account for L-Band presence from the start, eliminating the need for complex retroactive adjustments when L-Band hardware is added. This shifts the calibration complexity to the initial deployment stage when the system is being set up anyway.
Solution Approach 2:
The patent uses ASE noise sources as intermediaries to bridge the gap between initial C-Band-only deployment and future C+L dual-band operation. These noise sources act as a placeholder that simulates L-Band signals, allowing the system to be calibrated and optimized for dual-band operation without requiring actual L-Band hardware during the calibration process, thereby simplifying the upgrade path.
3Stability of the object's composition
If C-Band channels are engineered with extra margin, then performance stability is maintained during L-Band expansion, but initial signal power is reduced
Solution Approach 1:
The patent applies preliminary action by introducing ASE noise loading during initial C-Band deployment to pre-stress the system with the conditions that will exist during full dual-band operation. This allows the system to be optimized and balanced from the start with the knowledge of future L-Band presence, enabling operators to achieve performance stability without unnecessarily over-provisioning C-Band power margins. The noise loading reveals the actual system behavior under future operating conditions.
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
This approach simplifies control and network planning, enables accurate Raman amplifier calibration, and improves service restoration times by maintaining constant performance and deferring the cost of L-Band hardware, effectively doubling fiber capacity without performance degradation.
Implementation Method 1
both providing channelized Amplified Spontaneous Emission (ASE) loading in the C-Band and bulk ASE loading in the L-Band
Implementation Method 2
performance shifts between existing C-Band channels as the new L-Band signals appear due to Stimulated Raman Scattering (SRS)
Data Source
AI summary
An optical node supporting a modular deployment and upgrade of optical spectrum includes one or more C+L-Band amplifier modules; and a modular base module configured to interface one or more C-Band optical modems; wherein, in an initial deployment configuration, the modular base module provides channelized Amplified Spontaneous Emission (ASE) loading for select channels in the C-Band via a first ASE noise source coupled to a multiplexer for the C-Band, bulk ASE loading over the L-Band via a second ASE noise source coupled to an L-Band output, and an upgrade port for connection to an L-Band upgrade module. The L-Band upgrade module can selectively connect to the upgrade port to provide an L-Band upgrade configuration where the L-Band upgrade module and the modular base module coordinate transition of the bulk ASE loading to L-Band channelized ASE loading via a third ASE noise source.