Annular-Beam Coupling for Double-Clad Fiber Noise Reduction
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Solution Overview
Problem
Current imaging catheter systems, particularly those using double-clad fibers, suffer from noise issues due to autofluorescence components and Raman scattering signals generated in the core, which degrade image quality and contrast.
Innovation Solution
An annular-beam coupling system is introduced, where an annular beam is coupled to the cladding region of a double-clad fiber instead of the core, using components like axicon lenses, phase spatial filters, annular filters, and hollow core fibers to prevent light from entering the core, thereby reducing noise components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If light is coupled to the core of a double-clad fiber, then light transmission efficiency is improved, but noise components such as autofluorescence and Raman scattering increase
Solution Approach 1:
The invention segments the light coupling path by introducing a beam shaping element that divides the light beam into an annular configuration, separating the central core region from the cladding region. This segmentation allows selective coupling to the cladding while avoiding the core, thus reducing noise components while maintaining light transmission efficiency
Solution Approach 2:
The invention applies local quality by creating an annular beam profile with specific intensity distribution that concentrates light in the peripheral regions corresponding to the cladding area while minimizing intensity in the central core region. This localized light distribution enables effective coupling to the cladding while avoiding core-induced noise
2Object-generated harmful factors
If an annular beam is used to couple to the cladding region, then noise reduction is improved, but device complexity increases
Solution Approach 1:
The invention introduces a beam shaping element as an intermediary component between the light source and the double-clad fiber. This intermediary transforms the conventional Gaussian beam profile into an annular profile, enabling cladding-specific coupling. The use of this single intermediary component achieves noise reduction without requiring complex multi-component systems
Solution Approach 2:
The invention changes the spatial distribution parameter of the light beam from a conventional Gaussian profile to an annular profile. This parameter change is achieved through optical transformation using elements such as axicons or phase masks, which modify the beam's intensity distribution to concentrate light in the annular region corresponding to the cladding area, thereby reducing core-related noise while maintaining system simplicity
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 approach effectively reduces autofluorescence and Raman scattering noise, enhancing image quality and contrast by isolating the annular beam from the core, improving the signal-to-noise ratio and imaging speed.
Implementation Method 1
an axicon lens configured to convert the Gaussian beam into an annular beam
Implementation Method 2
a double-clad fiber configured such that the annular beam is coupled to its cladding region
Data Source
AI summary
Disclosed is an annular-beam coupling system enabling reduction of noise generated from a core of a double-clad fiber. The disclosed annular-beam coupling system comprises: a fiber for transmitting light of a light source; a collimator for receiving the light outputted from the fiber and forming a parallel beam of a circular shape; an annular-beam generation unit for converting the parallel beam into an annular beam; and a double-clad fiber having the annular beam coupled to a cladding region thereof.