Multi-core Fiber Pressure Sensor Temperature Compensation
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Solution Overview
Problem
Optical fiber pressure sensors in harsh environments, such as downhole settings, face challenges with temperature changes and drift sources, requiring additional sensors to compensate, which is costly and cumbersome.
Innovation Solution
A multi-core optical fiber pressure sensor with collocated measurement portions, such as Bragg gratings or in-fiber interferometers, where pressure-induced forces differentially affect the cores, eliminating temperature changes and drift by using cores with varying moduli or spatial relationships, and actuation mechanisms like bellows or diaphragms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pressure sensors are deployed near each other with different sensor characteristics to compensate for temperature changes and drift, then temperature compensation capability is improved, but device complexity and cost increase
Solution Approach 1:
The single optical fiber is segmented into multiple cores, each containing a measurement portion. This allows multiple measurement points to be integrated within one fiber structure, providing differential temperature compensation without requiring multiple separate sensor assemblies.
Solution Approach 2:
Multiple measurement functions are merged into a single multi-core optical fiber structure. The collocated measurement portions in different cores are integrated within the same fiber, eliminating the need for multiple separate sensors and reducing overall system complexity.
2Reliability
If multiple pressure sensors are deployed near each other with different sensor characteristics to compensate for temperature changes and drift, then temperature compensation capability is improved, but cost increases
Solution Approach 1:
The optical fiber is segmented into multiple cores during manufacturing, with each core containing a measurement portion. This segmentation is achieved in a single manufacturing process, reducing the cost compared to assembling multiple separate sensors.
Solution Approach 2:
Multiple measurement functions are merged into a single multi-core optical fiber structure. The collocated measurement portions in different cores are integrated within the same fiber, eliminating the need for multiple separate sensors and reducing overall system complexity.
3Reliability
If multiple pressure sensors are deployed near each other with different sensor characteristics to compensate for temperature changes and drift, then temperature compensation capability is improved, but installation and operation become tedious
Solution Approach 1:
The optical fiber is segmented into multiple cores, each containing a measurement portion. This segmentation is achieved in a single manufacturing process, reducing the cost compared to assembling multiple separate sensors.
Solution Approach 2:
Multiple measurement functions are merged into a single multi-core optical fiber structure. The collocated measurement portions in different cores are integrated within the same fiber, eliminating the need for multiple separate sensors and reducing overall system complexity.
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 simplifies and cost-reduces the elimination of temperature changes and drift sources, enabling accurate pressure measurements without the need for multiple sensors, by leveraging differential core reactions and actuation mechanisms to isolate temperature effects.
Implementation Method 1
the fiber is arranged such that a pressure induced force will act on the multi-core fiber affecting the collocated measurement portions in a different manner. In another exemplary embodiment, such arrangement causes one grating to be in compression and another to be in tension.
Implementation Method 2
the cores have collocated measurement portions, for example, in-fiber interferometers or Bragg grating portions
Implementation Method 3
the fiber is actuated by a pressure sensitive bellows or diaphragm. In another exemplary embodiment, the fiber is actuated by a force normal to the axis of the fiber.
Implementation Method 4
the fiber contains a lower modulus core near a first light guiding core and a higher modulus core near a second light guiding core. The provision of the multi-core fiber and the differential reaction of the pressure to the fiber portions containing the lower and higher modulus cores, respectively, at the measurement portions of the multiple cores, eliminate temperature changes or drift sources
Data Source
AI summary
A multi-core optical fiber pressure sensor is described, which sensor includes an optical fiber having at least two cores, wherein the cores have collocated measurement portions, for example in-fiber interferometers or Bragg Grating portions. In an exemplary embodiment, the fiber is arranged such that a pressure induced force will act on the multi-core fiber at said collocated position, affecting the light guiding cores in a different manner. In another exemplary embodiment, the optical fiber is configured to bend in response to pressure changes.