Per-Span Fiber Diagnostics Using Coherent Optical Supervisory Channels
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Solution Overview
Problem
Existing fiber-optic network sensing technologies face challenges in integrating per-span sensing without sacrificing available bandwidth, and transceiver-based sensing lacks precise fault location and access to information close to the fault.
Innovation Solution
A coherent optical supervisory channel (C-OSC) transceiver is used to perform per-span forward sensing and distributed acoustic sensing simultaneously, leveraging a narrow bandwidth channel, allowing direct integration into the network and enabling operators to access sensing data from intermediate nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transceiver-based sensing is used to monitor network state, then scalability and spectral efficiency are improved, but fault location precision deteriorates
Solution Approach 1:
The system segments the fiber network into multiple spans with individual sensing capabilities. Each transceiver performs sensing on its connected span, enabling distributed monitoring across the entire network while maintaining the ability to localize faults to specific segments rather than providing precise location within a single span.
2Reliability
If dedicated sensing bandwidth is allocated for distributed acoustic sensing, then sensing capability is improved, but available transmission bandwidth deteriorates
Solution Approach 1:
The optical supervisory channel is designed to serve multiple functions simultaneously: it provides network management and monitoring capabilities while also enabling distributed acoustic sensing. By making the supervisory channel multi-functional, the system avoids allocating separate dedicated bandwidth for sensing, thus preserving transmission bandwidth while maintaining sensing capability.
Solution Approach 2:
The system merges network management functions with sensing functions into a single integrated system. The coherent optical supervisory channel carries both management data and sensing signals, combining what were previously separate functions into one unified approach that eliminates the need for separate bandwidth allocation.
3Quantity of substance
If coherent optical supervisory channel is used for sensing, then bandwidth efficiency is improved, but access to intermediate node information deteriorates
Solution Approach 1:
The system implements feedback mechanisms where sensing data from intermediate nodes is extracted and fed back to network operators through the supervisory channel infrastructure. This allows operators to access real-time information from intermediate nodes without requiring direct termination of network traffic, maintaining both bandwidth efficiency and information accessibility.
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
The C-OSC system provides real-time sensing data extraction with minimal bandwidth impact, enabling precise fault location and direct access to network state information, enhancing network monitoring and fault detection capabilities.
Implementation Method 1
transceiver-based sensing uses the real-time readouts produced by coherent digital signal processing to measure phase and state of polarization (SOP) effects integrated over the transmitted link
Implementation Method 2
DAS is based on Rayleigh backscattering. It is very sensitive to mechanical effects and also allows for precise localization of events
Data Source
AI summary
A system and method are disclosed, in which data in an optical supervisory channel is transmitted from a first node of an optical fiber network to a second node of the optical fiber network and received in a coherent optical receiver at the second node of the optical fiber network. From a receiver output signal responsive to the received data, there is extracted at least one measure of phase variation and/or of signal attenuation on the optical fiber network between the first and second nodes.