Transverse LED Optical Fiber Sensor for High Spatial Resolution
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Solution Overview
Problem
Current spectroscopic optical fiber sensors for temperature and chemical species detection face challenges such as high complexity, manufacturing expense, and limited spatial resolution, particularly with axial excitation methods, which require expensive instrumentation and are prone to interference, while transverse excitation methods lack cost-effectiveness and refinement in spatial resolution.
Innovation Solution
A distributed optical fiber sensor system with a transversely positioned UV LED or white light LED as the probing light source, providing high spatial resolution and intensity, coupled with a sensitive optical fiber, detector, and signal processing means, allowing for precise measurement of temperature and chemical species across the fiber length with commercially available, inexpensive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If axial excitation is used to probe the sensitive cladding, then the fiber acts as a conduit for light interaction with the cladding, but the interaction is very small requiring high power source, expensive detection scheme, and very long optical fiber
Solution Approach 1:
The patent inverts the excitation approach from axial to transverse. Instead of sending light through the fiber core to interact with the cladding, the patent positions the light source perpendicular to the fiber axis, allowing direct evanescent field coupling between the light source and the sensitive cladding. This inversion dramatically increases interaction strength and eliminates the need for long fiber lengths and high power sources.
Solution Approach 2:
The patent introduces an evanescent field as an intermediary mechanism for light-matter interaction. By positioning the light source in transverse proximity to the fiber, the evanescent field extends from the light source into the sensitive cladding, creating a strong interaction region without requiring light to propagate through the entire fiber length.
2Ease of operation
If axial excitation with laser is used, then light can be delivered to reactant regions, but collinear alignment of light source with fiber axis is challenging requiring careful handling and calibration
Solution Approach 1:
The patent inverts the alignment challenge by changing from axial to transverse excitation geometry. Instead of requiring precise collinear alignment along the fiber axis, the light source is positioned perpendicular to the fiber, creating a more robust alignment configuration that is insensitive to small positional variations and eliminates the need for complex calibration procedures.
3Measurement precision
If transverse excitation is used to probe sensitive regions, then superior technique is achieved, but cost-effectiveness and refinement in spatial resolution are lacking
Solution Approach 1:
The patent replaces expensive lasers and complex instrumentation with inexpensive LED light sources. The LED-based transverse excitation system achieves comparable or superior spatial resolution while dramatically reducing manufacturing costs and system complexity, making the technology economically viable for widespread deployment.
4Adaptability or versatility
If several cladding sections are removed and bare core regions are coated with reactive agent, then distributed sensing is achieved, but manufacturing complexity and expense increase
Solution Approach 1:
The patent inverts the sensing approach by maintaining the intact fiber structure and using transverse excitation to probe the cladding. Instead of removing cladding sections to create bare core regions, the patent keeps the fiber intact and uses the evanescent field of the transverse light source to interact with the sensitive cladding, greatly simplifying manufacturing while maintaining distributed sensing capability.
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 system achieves high spatial resolution of less than 5 mm, reduces manufacturing costs, and enhances robustness, enabling precise detection of chemical species and temperature variations along the fiber with improved spatial resolution and resistance to interference, while being adaptable to various chemical species and spectral regions.
Implementation Method 1
A distributed optical fiber sensor system with a transversely positioned UV LED or white light LED as the probing light source
Implementation Method 2
absorption, fluorescent, phosphorescent and chemiluminescent based sensors
Implementation Method 3
absorption, fluorescent, phosphorescent and chemiluminescent based sensors
Implementation Method 4
absorption, fluorescent, phosphorescent and chemiluminescent based sensors
Implementation Method 5
absorption, fluorescent, phosphorescent and chemiluminescent based sensors
Data Source
AI summary
A spectroscopic based optical fiber sensor includes a sensitive optical fiber, a probing light source, a power supply, a detector means, a signal processing means, and a display means. The sensitive optical fiber is optically affected by the presence of at least one measurand. The probing light source, adjacent to the sensitive fiber, transversely illuminates the fiber from the outside. The probing light is modified by the sensitive fiber, coupled into the optical fiber core, either as bound modes or leaky modes, as a light signal and guided to a detector means located at the terminus of the optical fiber. The detector means correlates the intensity of the light signal with an electric signal and transmits the electric signal to the signal processing means, wherein the electric signal is correlated to the quantity being measured. The correlated quantity being transmitted and displayed on the display means.