Optical Fiber Termination Taper for High-M2 Laser Coupling
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Solution Overview
Problem
Existing fiber termination technologies for high-energy laser pulses, particularly those from holmium lasers, suffer from inefficiencies in coupling light into optical fibers, leading to damage and failure due to misalignment, cladding mode excitation, and attenuation, which are not adequately addressed by current designs.
Innovation Solution
A one-piece optical fiber termination apparatus that spatially reshapes light without additional lenses, using a passive optical taper with constant core and cladding diameters and specific dielectric boundaries to ensure single-direction propagation and minimize reflections, thereby improving coupling efficiency and reducing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fiber termination designs are used with high-energy laser pulses, then coupling of laser light into optical fibers is achieved, but misalignment and cladding mode excitation cause damage and failure
Solution Approach 1:
The patent merges the fiber core and cladding into a single integrated structure where the cladding is formed by stretching the fiber core material itself, eliminating the need for separate cladding materials and complex assembly processes. This unified structure inherently prevents misalignment issues while maintaining optical performance
Solution Approach 2:
The invention changes the physical parameters of the fiber structure by controlling the stretching process to create specific core-clad diameter ratios and refractive index profiles. By adjusting stretch ratios and heating conditions, the patent optimizes the fiber's ability to handle high-energy laser pulses without damage
2Productivity
If additional lenses and complex optical systems are used to improve coupling efficiency, then light coupling performance improves, but fabrication complexity and alignment requirements increase
Solution Approach 1:
The patent extracts and eliminates the need for additional lenses and complex optical components by designing the fiber structure itself to perform the light coupling function. The specialized core-clad structure directly guides and focuses laser light without requiring external optical elements
Solution Approach 2:
The fiber structure serves its own optical function through its inherent refractive index profile and geometry. The cladding region, formed by stretching the core material, automatically provides the necessary optical guidance and focusing effects without external assistance
3Loss of energy
If conventional fiber termination designs are used, then basic light transmission is achieved, but cladding mode excitation and attenuation lead to energy loss
Solution Approach 1:
The patent optimizes the physical parameters of the fiber structure, including core diameter, cladding diameter, and refractive index differences, to minimize cladding mode excitation and optical energy loss. The stretching process parameters are carefully controlled to achieve optimal performance
Solution Approach 2:
The invention creates distinct local regions within the fiber structure with different optical properties. The core region maintains high refractive index for light guidance, while the stretched cladding region provides appropriate refractive index contrast to prevent energy loss and minimize attenuation
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 solution enhances coupling efficiency, reduces damage to optical fibers, and simplifies fabrication by eliminating the need for complex alignment and lens-based systems, ensuring reproducible and robust performance.
Implementation Method 1
a passive optical taper with constant core and cladding diameters and specific dielectric boundaries to ensure single-direction propagation and minimize reflections
Implementation Method 2
configured to radiatively couple optical waveguides such as optical fibers and sources of laser radiation
Data Source
AI summary
An article of manufacture including a fiber optic termination of a small core optical fiber for use with a surgical laser apparatus (the output from which may, in a specific case, be characterized by a high M2 factor) or other high-power or high-energy laser (including an appropriate fiber laser) is configured for safe and efficient coupling of light at a large laser focal point and/or to enable the process of coupling of radiant intensities exceeding the silica fiber damage thresholds and/or those ionizing the air if fully focused therein. The termination may include a glass cylinder structured to include a core region and a glass cladding region the ratio of dimensions of which is substantially equal to the ratio of respectively-corresponding dimensions of the employed optical fiber. A method of propagating light through such article of manufacture.