Subchannel Photonic Routing for WDM Network Upgrades
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Solution Overview
Problem
Current optical WDM communication systems face challenges in achieving higher transmission speeds and flexibility in routing client signals, as well as managing network upgrades and maintaining visibility within multichannel optical networks.
Innovation Solution
The implementation of subchannel photonic routing, switching, and protection using tunable lasers to generate subcarrier frequencies, allowing for flexible mapping and routing of client signals across multiple subchannels within and across ITU channels, and the use of novel architectures and devices such as subchannel muxponders, crossponders, and cyclical filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the bandwidth of a fiber channel is increased from 10 Gb/s to 40 Gb/s, then the transmission capacity is improved, but the flexibility in routing individual client circuits is reduced
Solution Approach 1:
The patent divides a single 40 Gb/s optical channel into four separate 10 Gb/s subchannels using wavelength division multiplexing. Each subchannel can be independently routed and assigned to different client circuits, thereby maintaining routing flexibility while achieving high transmission capacity. This is accomplished through the use of subchannel transponders that can selectively map client signals to specific subchannels and subchannel add-drop multiplexers that can independently handle each subchannel.
2Adaptability or versatility
If subchannel routing and switching capabilities are added to WDM optical networks, then the flexibility and bandwidth are improved, but the device complexity increases
Solution Approach 1:
The patent designs subchannel transponders and subchannel add-drop multiplexers that can operate with both 10 Gb/s and 40 Gb/s channels, providing multi-functionality. These devices can dynamically adapt to different channel configurations, allowing networks to upgrade from 10 Gb/s to 40 Gb/s without replacing all equipment. The subchannel transponders can function as either full 40 Gb/s transponders or as four separate 10 Gb/s transponders, reducing overall device complexity while maintaining flexibility.
3Ease of manufacture
If legacy 10 Gb/s WDM network equipment is reused during upgrades to 40 Gb/s, then the upgrade cost is reduced, but the loss of information or control over individual client circuits increases
Solution Approach 1:
The patent introduces subchannel transponders as intermediary devices between legacy 10 Gb/s network equipment and new 40 Gb/s requirements. These subchannel transponders maintain the external interface of traditional transponders, allowing them to interoperate with legacy add-drop multiplexers and network management systems. Internally, they provide subchannel-level control and mapping capabilities, thereby preserving control visibility while enabling cost-effective upgrades by reusing existing legacy equipment.
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 significantly increases the number of optical circuits in a fiber, enhancing bandwidth and spectral efficiency, while enabling dynamic routing, switching, and protection capabilities with minimal disruption to live networks.
Implementation Method 1
tunable lasers to generate subcarrier frequencies, allowing for flexible mapping and routing of client signals across multiple subchannels
Implementation Method 2
Optical WDM communication systems transmit multiple optical channels at different WDM carrier wavelengths through a single fiber
Data Source
AI summary
The present invention includes novel techniques, apparatus, and systems for optical WDM communications. Tunable lasers are employed to generate respective subcarrier frequencies which represent subchannels of an ITU channel to which client signals can be mapped. In one embodiment, subchannels are polarization interleaved to reduce crosstalk. In another embodiment, polarization multiplexing is used to increase the spectral density. Client circuits can be divided and combined with one another before being mapped, independent of one another, to individual subchannels within and across ITU channels. A crosspoint switch can be used to control the client to subchannel mapping, thereby enabling subchannel protection switching and hitless wavelength switching. Network architectures and subchannel transponders, muxponders and crossponders are disclosed, and techniques are employed (at the subchannel level/layer), to facilitate the desired optical routing, switching, concatenation and protection of the client circuits mapped to these subchannels across the nodes of a WDM network.