Loopback Architecture for Undersea DAS Range Extension
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Solution Overview
Problem
Conventional distributed acoustic sensing (DAS) systems have limited range and sensing capabilities, especially in undersea optical cables, requiring multiple standalone optoelectronic devices and being impractical and expensive for long-range subsea applications.
Innovation Solution
The implementation of a high-loss loopback architecture that transmits and amplifies DAS signals along multiple spans of optical fibers, allowing the signal to be routed and amplified back to a DAS device, extending the sensing range and enabling span-specific detection through optical filters and switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If multiple standalone optoelectronic devices are used to extend DAS range, then the sensing range is improved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent merges multiple DAS sensing segments into a single integrated system by using loopback architecture. Instead of deploying multiple standalone optoelectronic devices, the system uses a single DAS device combined with loopback configurations that enable extended sensing range through signal routing and amplification along the optical fiber.
Solution Approach 2:
The patent introduces optical amplifiers and loopback configurations as intermediary components between the DAS device and the remote sensing points. These intermediaries enable signal transmission and amplification over extended distances without requiring additional standalone DAS devices, thus reducing system complexity while maintaining extended sensing range.
2Length of stationary object
If multiple standalone optoelectronic devices are deployed, then the sensing range is extended, but the cost increases significantly
Solution Approach 1:
The patent combines multiple sensing functions into a single integrated DAS system using loopback architecture. This consolidation eliminates the need for multiple expensive standalone optoelectronic devices, thereby significantly reducing system cost while achieving extended sensing range through clever signal routing and amplification.
Solution Approach 2:
The patent uses optical amplifiers as intermediary components to extend the sensing range without requiring additional standalone DAS devices. These amplifiers act as cost-effective mediators that enable signal transmission over long distances, reducing the overall system cost compared to deploying multiple complete DAS systems.
3Length of stationary object
If the DAS range is extended using conventional methods, then the sensing capability is improved, but the interrogation rate decreases
Solution Approach 1:
The patent segments the optical fiber into multiple spans with intermediate amplification points. By dividing the long fiber into manageable segments separated by optical amplifiers, the system maintains high interrogation rates across the entire extended range. Each segment can be interrogated independently with high frequency, and the amplifiers ensure sufficient signal strength at each segment.
Solution Approach 2:
The patent introduces optical amplifiers as intermediaries at strategic points along the fiber to maintain signal strength for high-rate interrogation. These amplifiers enable the system to sustain high interrogation rates over extended distances by compensating for signal attenuation in each fiber segment, thus resolving the trade-off between range and interrogation rate.
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 solution significantly extends the DAS range beyond a single fiber span, allowing for flexible and variable range extension, maintaining high interrogation rates over long distances with a single DAS device, and enabling effective monitoring of subsea activities.
Implementation Method 1
the DAS system may be based on Rayleigh scattering (otherwise referred to as a Rayleigh-scattering-based DAS system). In this system, a coherent laser pulse may be sent along an optical fiber, and scattering sites within the optical fiber may cause the fiber to act as a distributed interferometer
Implementation Method 2
transmitting and amplifying a DAS signal along multiple spans of a first optical fiber
Data Source
AI summary
Apparatus, systems, and techniques for extending distributed acoustic sensing (DAS) range in undersea optical cables over multiple spans, as well as providing span-specific DAS information, are provided.