Fiber Endoscope Double-Clad Coupler Noise Reduction
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Solution Overview
Problem
Existing fiber endoscope configurations suffer from undesired background signals due to native fluorescence and Raman scattering, which can overwhelm the desired signal and reduce the signal-to-noise ratio, especially in longer fibers used for internal body imaging.
Innovation Solution
The design minimizes noise by keeping the length of the fibers carrying both source illumination and collected light as short as possible, using a double-clad fiber coupler close to the distal end or scanning mechanism, and employing flexible double-clad fiber couplers to reduce bending radius, thereby separating the source light path from the signal light path and minimizing noise creation in the fiber core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If longer fibers are used to reach remote body locations, then the imaging capability is improved, but the background noise from native fluorescence and Raman scattering increases, reducing the signal-to-noise ratio
Solution Approach 1:
The fiber bundle is divided into separate source fibers and signal fibers that are kept as short as possible. The fiber coupler is positioned at the distal end to minimize the length of fibers carrying excitation light, thereby reducing the generation of background noise while maintaining the ability to reach remote imaging locations.
Solution Approach 2:
The harmful background noise generation is extracted from the system by minimizing the length of source fibers. The fiber coupler design separates the excitation light path from the signal collection path, allowing the source fibers to be kept short and thus removing the source of Raman scattering and native fluorescence that would occur in longer fibers.
2Object-generated harmful factors
If the source light path and signal light path are kept separate for most of the distance, then the noise from excitation light bleeding into cladding is minimized, but the device complexity increases
Solution Approach 1:
The source fibers and signal fibers are merged into a single fiber bundle structure that is inserted through a single catheter lumen. The fiber coupler integrates multiple fiber endings at the distal end, combining separate light paths into a unified probe structure that minimizes noise while avoiding the complexity of multiple separate catheters.
Solution Approach 2:
The fiber bundle with separate source and signal fibers is nested within the catheter structure. The fiber coupler is positioned at the distal end of the catheter, creating a nested configuration where the complex fiber arrangement is contained within the simpler catheter structure, 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 approach significantly reduces noise contribution, improving the signal-to-noise ratio and enabling more effective imaging in remote body locations with reduced interference from background signals.
Implementation Method 1
a fiber bundle comprising a plurality of double-clad fibers, each double-clad fiber comprising a fiber core and a fiber cladding surrounding the fiber core
Implementation Method 2
these effects may include native fluorescence and Raman scattering background signals generated in the fiber
Implementation Method 3
these effects may include native fluorescence and Raman scattering background signals generated in the fiber
Implementation Method 4
a fiber coupler forming an optical connection between at least the source fibers and the sampling fibers and between the sampling fibers and the signal fibers
Data Source
AI summary
A fibre endoscope system (100) comprises a catheter (10) with a probe head (10a) for entering into a body cavity (C) adjacent or near a sample region (S). A source fiber (11) has a first fiber ending (11a) and a signal fiber (12) has a second fiber ending (12a) both remote from the probe head (10a) but separate. A sampling fiber (13) has a third fiber ending (13a) disposed at the probe head (10a). A fiber coupler (15) is configured to optically couple at least the source fiber (11) to the sampling fiber (13), and the sampling fiber (13) to the signal fiber (12). A sampling fiber length (L13) of the sampling fiber (13) between a fiber coupler (15) and the third fiber ending (13a) is shorter than a source fiber length (L11) of the source fiber (11) between the fiber coupler (15) and the first fiber ending (11a).