Fibre Optical Combiner with Annular High-Index Regions
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Solution Overview
Problem
Existing methods for combining laser outputs into a single optical fibre often result in uniform light distributions, which are not suitable for applications requiring tailored, non-uniform profiles like annular profiles, and involve complex free-space optics, especially in high-power fibre-laser systems.
Innovation Solution
A fibre optical combiner with a double-clad output fibre and annular high-index regions that selectively couple light from a subset of input fibres, creating an annular peak intensity profile, enhancing brightness and simplifying the process compared to bulk optic schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a standard output fibre with uniform refractive index is used to combine laser inputs, then all inputs are overlapped and a uniform circularly symmetric output is produced, but this prevents achieving tailored non-uniform light distributions
Solution Approach 1:
The output fibre is designed with non-uniform refractive index regions (first and second regions with different refractive indices) that create specific optical paths for different input fibres. This local variation in refractive index allows different spatial regions of the fibre to handle light differently, producing tailored output profiles such as annular distributions while maintaining a single fibre structure.
2Adaptability or versatility
If free-space optics are used to produce tailored light distributions, then non-uniform profiles can be achieved, but the system becomes complex and unsuitable for high-power fibre-laser systems
Solution Approach 1:
The patent merges the functions of multiple input fibres carrying different spatial modes into a single output fibre with engineered refractive index regions. The first and second refractive index regions work together to guide and shape light from multiple inputs, combining the advantages of fibre-based delivery with tailored output profiles, thereby eliminating the need for complex free-space optical components.
3Power
If multiple input fibres are spliced to a standard output fibre, then high power combining is achieved, but the output profile remains uniform and cannot be tailored
Solution Approach 1:
The output fibre incorporates spatially varying refractive index regions that create different optical pathways for light from different input fibres. The first region with higher refractive index and the second region with lower refractive index work together to shape the combined light, enabling tailored output profiles such as annular distributions while maintaining the high power combining capability of multiple fibre inputs.
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 enables robust, efficient production of non-uniform light distributions, increasing brightness and allowing for rapid switching of beam profiles, suitable for various laser processing applications, including welding and cutting, with faster switching times than traditional methods.
Implementation Method 1
The beam emitted from such a fibre is thus also circularly symmetric and produces a generally uniform distribution of light on a workpiece receiving a laser beam via the beam delivery optical fibre
Data Source
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AI summary
An optical combiner (25), comprising a bundle of input fibres (24) spliced to an output fibre (26), the output fibre having a cladding and at least one high-index portion within the cladding, such that the high index portion has a diameter substantially equal to or less than the outer diameter of the input fibre bundle at the splice point.