Fibre Optic Sensing Device Multiplexed Interferometry
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Solution Overview
Problem
Existing multipoint vibration measurement systems using interferometric sensors become increasingly complex and costly as the number of measurement points grows, due to the need for additional lasers and detectors.
Innovation Solution
A fibre optic sensing device utilizing a common laser and detector, where each optical fibre portion has a unique optical path length and includes a sensor with a third reflector whose position varies based on the parameter being sensed, allowing for multiplexed interferometric signals to be distinguished using range-resolved interferometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional lasers and detectors are provided to measure vibrations of increased number of points, then the measurement capability is improved, but the system size and complexity increase
Solution Approach 1:
The patent combines multiple measurement functions into a single laser and detector system. By using a single laser source that illuminates multiple sensors and a single detector that receives reflected light from all sensors, the system eliminates the need for multiple independent laser-detector pairs, thereby reducing system size and complexity while maintaining multi-point measurement capability
Solution Approach 2:
The single laser and detector are designed to serve multiple measurement points simultaneously. The laser provides illumination for all sensors and the detector receives signals from all measurement points, making these components universal rather than dedicated to specific points, thus improving adaptability without increasing device complexity
2Adaptability or versatility
If additional lasers and detectors are provided to measure vibrations of increased number of points, then the measurement capability is improved, but the system cost increases
Solution Approach 1:
The patent merges multiple expensive laser and detector components into single shared components. By having one laser serve multiple sensors and one detector receive signals from multiple measurement points, the overall system cost is reduced while maintaining the capability to measure vibrations at multiple points
3Measurement precision
If individual detectors and lasers are used for each measurement point, then the measurements from each sensor can be distinguished, but the system becomes complex as the number of measurement points increases
Solution Approach 1:
The patent introduces local quality variations in the form of unique optical path lengths for each sensor-detector path. Each measurement point has a distinct optical path length that serves as its identifier, allowing the single detector to distinguish between signals from different sensors based on their unique path characteristics without requiring multiple detectors
Solution Approach 2:
The system uses parameter changes in the optical path length as a distinguishing feature for each measurement point. By varying the optical path length for each sensor path and using signal processing to analyze these differences, the system can distinguish between multiple measurement points while using a single detector, thereby reducing 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
Enables efficient multipoint vibration measurements with a single laser and detector, reducing system size, complexity, and cost while maintaining accurate sensor readings by using a common light source and detector across multiple fibre optic paths with distinct optical path lengths.
Implementation Method 1
a fibre optic sensing device comprising a plurality of optical fibre portions, wherein each optical fibre portion is arranged to receive laser light from a common laser
Implementation Method 2
each optical fibre portion comprises a first reflector spaced from a distal end of the optical fibre portion and a second reflector at the distal end
Implementation Method 3
the sensor is configured such that a physical property between the second and third reflectors varies depending on a parameter being sensed
Data Source
Figure 1
Figure 2~3a
Figure 3b
AI summary
A fibre optic sensing device is provided. The fibre optic sensing device comprises a plurality of optical fibre portions, wherein each optical fibre portion is arranged to receive laser light from a common laser and reflect the laser light to a common detector, wherein each optical fibre portion comprises a first reflector spaced from a distal end of the optical fibre portion and a second reflector at the distal end, wherein each optical fibre portion comprises a sensor provided at the respective distal end of the optical fibre portion, the sensor comprising a third reflector the position of which varies depending on a value of a property being sensed, wherein a distance between the first and second reflectors is different for each of the optical fibre portions.