Coexisting GPON and XGPON Optical Network with Raman Amplification
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Solution Overview
Problem
Current passive optical network (PON) systems are limited in reach and split ratio, and the coexistence of gigabit (GPON) and 10-gigabit (XGPON) systems within the same architecture is challenging, particularly in maintaining a purely passive distribution network while accommodating different data rates and wavelengths.
Innovation Solution
The use of counter-propagating laser pump sources at the optical line terminal (OLT) for Raman amplification of upstream signals, combined with separate power splitters and cyclic wavelength division multiplexing at the remote node, allows for optimized split ratios and extended reach for both GPON and XGPON systems, enabling their coexistence while maintaining a passive network architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single passive optical splitter is used for both GPON and XGPON systems, then device complexity is reduced, but the split ratio cannot be optimized for each data rate separately, limiting system performance
Solution Approach 1:
The patent divides the single power splitting function into separate power splitters for GPON and XGPON systems. This segmentation allows each splitter to be independently optimized for its specific data rate requirements, resolving the contradiction between device simplicity and performance optimization.
2Length of stationary object
If Raman amplification is implemented to extend reach, then the reach is increased to 50 km, but the device complexity and power consumption increase due to additional pump sources
Solution Approach 1:
The pump sources are designed to serve dual purposes: amplifying upstream signals for both GPON and XGPON systems simultaneously. This multi-functionality allows reach extension without proportionally increasing device complexity, as the same pump infrastructure supports multiple data rates.
3Adaptability or versatility
If separate power splitters are used for GPON and XGPON, then split ratio is optimized for each system, but the device complexity increases
Solution Approach 1:
The patent changes the splitting ratio parameters independently for GPON and XGPON systems by using separate power splitters. This allows each system to operate at its optimal split ratio (e.g., 1:64 for GPON and 1:32 for XGPON), achieving parameter optimization that directly resolves the contradiction.
4Ease of operation
If a purely passive network architecture is maintained, then ease of operation and reliability are improved, but the ability to implement advanced features like Raman amplification is limited
Solution Approach 1:
The patent introduces pump sources as intermediary active components that enable Raman amplification without compromising the passive nature of the distribution network. These intermediaries are strategically placed at the OLT side, allowing advanced amplification features while maintaining the passive splitter architecture that ensures ease of operation and reliability.
Data Source
AI summary
A passive, coexisting 10 Gb/s passive optical network (XGPON) and Gb/s passive optical network (GPON) is created by using a pair of counter-propagating laser pump sources at a network-based optical line terminal, in combination with a feeder fiber, to create distributed Raman amplification for the upstream signals associated with both GPON and XGPON systems. A passive remote node is located at the opposite end of the feeder fiber, in the vicinity of a group of end-user locations, and includes a cyclic WDM and a pair of power splitters for the GPON and XGPON signals such that the GPON signals are thereafter directed through a first power splitter into optical network units (ONUs) specifically configured for GPON wavelengths and XGPON signals are directed through a second power splitter into ONUs configured for the XGPON wavelengths. The arrangement of the remote node allows for the reach and split ratios of the GPON and XGPON systems to be individually designed for optimum performance.