Multi-core FBG Probe Fabrication via Capillary Self-Assembly
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Solution Overview
Problem
Existing multi-core fiber Bragg grating (FBG) probes face limitations due to restricted parameter design, intense crosstalk during FBG inscription, and high insertion loss, which affect their accuracy and cost-effectiveness for micro-part measurements.
Innovation Solution
A fabrication method using capillary self-assemble technique to reduce fiber diameter, align and assemble multiple FBG fibers into a compact bundle, and polish the terminal to create a multi-core FBG probe with customizable parameters, avoiding crosstalk and reducing insertion loss by eliminating the need for fan-out devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-core fiber is selected from manufacturers' existing types, then the probe can be manufactured, but the parameter design is restricted and cannot be customized according to measurement requirements
Solution Approach 1:
The multi-core fiber is divided into individual single-core fibers, each inscribed with FBG independently. These separate fibers are then assembled into a bundle with customizable spatial arrangements, enabling flexible parameter design while avoiding the limitations of pre-manufactured multi-core fibers.
Solution Approach 2:
The patent transitions from selecting from fixed manufacturer types (0D/1D selection) to customizing in multiple dimensions including fiber diameter, core spacing, bundle configuration, and FBG parameters. This dimensional expansion allows tailored probe design for specific measurement applications.
2Reliability
If FBG is inscribed on the fiber cores of multi-core fiber, then the probe functionality is achieved, but intense crosstalk occurs among the inscription of FBGs on each fiber core
Solution Approach 1:
Instead of inscribing FBG on a multi-core fiber where crosstalk occurs between cores, the patent segments the multi-core fiber into individual single-core fibers. Each fiber is inscribed with FBG separately, eliminating the crosstalk problem while maintaining the multi-sensing capability through the fiber bundle arrangement.
3Loss of energy
If a brought multi-core fiber is used directly, then the probe can be fabricated, but the insertion loss is high and fan-out devices are required
Solution Approach 1:
Instead of using a multi-core fiber and splitting the signal (fan-out approach), the patent inverts the approach by using multiple independent single-core fibers, each carrying its own FBG signal. This eliminates the need for fan-out devices and reduces insertion loss associated with signal splitting.
4Volume of moving object
If the diameter of the fiber is reduced using mechanical or etch method, then the fiber can be assembled into compact bundle, but the manufacturing process becomes more complex
Solution Approach 1:
The patent changes the diameter parameter of the fiber to enable compact bundling. By reducing the fiber diameter through controlled processes, the fibers can be tightly packed into a small bundle while maintaining manageable fabrication complexity through systematic processing steps.
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 method enables flexible parameter design, improved spectral characteristics, high reflectivity, and reduced fabrication costs, enhancing the accuracy and applicability of multi-core FBG probes for micro-part measurements.
Implementation Method 1
the UV adhesive is raised in the gaps between the fibers
Implementation Method 2
the capillary bridge between the fibers is formed; a most compact structure of the fiber bundle is formed as a result of the capillary self-assembly
Implementation Method 3
the fiber bundle is cured using a UV light and the multi-core FBG is therefore formed
Data Source
AI summary
A fabrication method of a multi-core fiber Bragg grating (FBG) probe for measuring structures of a micro part based on the capillary self-assembly technique, wherein the diameter of the fiber (6) inscribed with FBG is reduced using a mechanical method or an etch method by the hydrofluoric acid; the fibers (6) inscribed with FBG, whose diameter has been reduced, are inserted into a tube (7) through its terminal with an inner taper angle; the FBG terminals of these fibers (6) are immersed into the UV adhesive (10) of a low viscosity and the UV adhesive (10) is raised in the gaps between the fibers (6); or the UV adhesive is dropped on these fibers (6) and the capillary bridge between the fibers (6) is formed; a most compact structure of the fiber bundle is formed as a result of the capillary self-assembly; the fiber bundle is cured using a UV light and the multi-core FBG (11) is therefore formed; the terminal of the multi-core FBG (11) is polished with an optic fiber polishing machine and then a spherical tip is fabricated with the melting fiber method or the installation method of a micro ball; therefore, a multi-core FBG (11) probe can be achieved. The method features low crosstalk between signal of FBG, inexpensive and low insertion loss.