Optical Network Connection Restoration Using Coherent Detection
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Solution Overview
Problem
Optical communication networks face challenges in rapidly restoring connections due to the time-consuming adjustment of dispersion compensation modules, which is critical for minimizing signal loss during failures, especially since existing solutions require expensive equipment or large form factors that are not cost-effective for widespread installation.
Innovation Solution
The method employs a combination of optical receivers with quadratic detection and coherent detection capabilities, utilizing adjustable dispersion compensation modules and switching mechanisms to quickly adapt to changes in dispersion along new optical paths during connection restoration, allowing for efficient use of resources and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If thermal control modules are used for dispersion compensation, then the equipment is compact and cost-effective, but the adjustment time is too long (several minutes)
Solution Approach 1:
The patent introduces a coherent detection receiver as an intermediary device to measure dispersion values quickly. This mediator receiver provides rapid dispersion measurements without replacing the standard quadratic detection receivers, thus reducing adjustment time while maintaining system simplicity and cost-effectiveness.
2Loss of time
If coherent detection receivers are used, then fast adaptation to dispersion changes is achieved, but the equipment cost and complexity increase significantly
Solution Approach 1:
The patent applies partial coherent detection by using a dedicated coherent detection receiver only for dispersion measurement purposes during restoration, rather than replacing all receivers. This partial application provides the necessary fast adaptation capability while avoiding the full cost and complexity of universal coherent detection deployment.
Solution Approach 2:
The coherent detection receiver serves as a specialized intermediary tool used temporarily during restoration operations to quickly characterize dispersion, after which standard quadratic detection receivers resume normal operation. This intermediary approach provides fast adaptation without permanently increasing system complexity.
3Adaptability or versatility
If multiple compensation fibers are used to cover broad dispersion range, then dispersion compensation capability is improved, but the form factor becomes too large for card installation
Solution Approach 1:
The patent replaces the mechanical/optical approach of using multiple physical compensation fibers with an electronic/digital approach using coherent detection for measurement and electronic control of compensation modules. This substitution eliminates the need for multiple fiber types and large form factors while maintaining broad dispersion compensation capability.
Solution Approach 2:
Instead of changing physical fiber parameters (using different fiber types with different dispersion characteristics), the patent changes the control parameters of electronic compensation modules based on dispersion values measured by the coherent detection receiver. This parameter-based approach provides flexible adaptation without increasing physical form factor.
4Loss of time
If protective connections are established, then connection restoration is nearly immediate, but the cost is very high due to doubled transmission capacities
Solution Approach 1:
The patent implements preliminary action by pre-characterizing the dispersion properties of alternative optical paths using coherent detection receivers before actual failures occur. When a failure happens, the system can quickly calculate and switch to a pre-characterized alternative path with known dispersion values, achieving fast restoration without needing duplicate protective connections.
Solution Approach 2:
The coherent detection receiver provides real-time feedback on dispersion values along different optical paths, enabling the system to intelligently select and adapt to the best alternative path during restoration. This feedback mechanism allows efficient use of existing transmission capacity rather than requiring doubled capacity for protective connections.
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 enables fast adaptation to dispersion changes, reducing restoration time and maintaining signal quality, while being cost-effective and compact enough for installation on network cards, thus offering a viable alternative to traditional restoration methods.
Implementation Method 1
at least one optical receiver based on a coherent detection of the signal transmitted by the connection capable of compensating for the dispersion effects accumulated along the connection's optical path
Implementation Method 2
a plurality of optical receivers based on a quadratic detection of the signal transmitted by a source node and equipped with adjustable modules for compensating for the dispersion effects
Data Source
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AI summary
The present invention pertains to a method for restoring an optical connection linking a source node to an egress node of an optical network, wherein a node comprises: ― a plurality of optical receivers based on a quadratic detection of the signal transmitted by a source node and equipped with adjustable modules for compensating for the dispersion effects which have accumulated on the connection's optical path between a source node and an egress node, ― switching means making it possible to send signals in which said node is the egress node towards at least one optical receiver of said node, said egress node further comprising: - at least one optical receiver based on a coherent detection of the signal transmitted by the connection capable of compensating for the dispersion effects accumulated along the connection's optical path and enabling a fast adaptation to a change in the value of the dispersion, wherein, in the event of failures on a connection, said method comprises the following steps: - determining a new optical path that makes it possible to restore the optical connection between the source node and the egress node, - activating the connection corresponding to the determined new optical path, - sending the signal transmitted by the connection corresponding to the determined new optical path to an optical receiver, based on a coherent detection of the signal transmitted by the connection, - adjusting the compensation module associated with the receiver based on a quadratic detection of the connection that has experienced a failure in order to compensate for the scatter effects that have accumulated on the new optical path, once the adjustment is made, - deleting the sending of the signal transmitted by the connection corresponding to the determined new optical path to an optical receiver, based on a coherent detection of the signal transmitted by the connection.