Fat-Fiber Adapter for High-NA Pump Coupling
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Solution Overview
Problem
Conventional fiber-based gain systems face limitations in efficiently coupling high numerical aperture (NA) pump light, leading to restricted power output and increased risk of fiber failure due to the architecture of tapered fiber bundles and glass-clad pump fibers, which restrict the number of pump fibers that can be combined and result in inefficient energy transfer.
Innovation Solution
A novel non-tapered high NA pump and signal combiner architecture that allows for the efficient coupling of high NA pump light outside the lasing cavity, using a fat-fiber adapter to split and combine pump light with a signal fiber, and employing cladless inputs to increase the number of pump fibers that can be combined, thereby reducing fiber failure risks and enhancing power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If tapered fiber bundles with glass-clad pump fibers are used, then fiber structure integrity is maintained, but the number of pump fibers that can be combined is restricted and coupling efficiency of high NA pump light deteriorates
Solution Approach 1:
The patent removes the glass cladding from pump fibers to create cladless pump fibers, extracting the limiting factor that prevented efficient coupling of high NA pump light. This allows the pump fiber cores to be directly combined with the signal fiber core in a fused fiber bundle, enabling effective coupling of high NA pump light without the energy loss associated with glass cladding interfaces.
Solution Approach 2:
The patent creates a composite structure by fusing multiple cladless pump fiber cores directly with the signal fiber core to form an integrated fused fiber bundle. This composite approach allows direct optical coupling between pump and signal modes, enabling efficient energy transfer from multiple pump fibers to the signal fiber without requiring traditional glass cladding boundaries.
2Power
If more pump fibers are combined to increase power output, then power capacity increases, but fiber failure risk increases due to architecture limitations
Solution Approach 1:
By removing the glass cladding from pump fibers, the patent eliminates the structural complexity and potential failure points associated with multiple cladded fiber interfaces. The cladless design simplifies the fiber bundle architecture, reducing stress concentration points and enabling more reliable operation at higher power levels.
Solution Approach 2:
The patent merges the pump fiber cores directly with the signal fiber core in a unified fused fiber bundle structure. This integration creates a more robust architecture where pump and signal modes co-propagate together, distributing mechanical stress more evenly and reducing the risk of fiber failure compared to traditional separate cladded fiber arrangements.
3Ease of manufacture
If conventional tapered fiber bundle architecture is used, then manufacturing process is established, but coupling of partitioned high NA pump light outside lasing cavity is inefficient
Solution Approach 1:
The patent performs the fiber combining operation before the fibers are subjected to high power operation, creating a pre-assembled fused fiber bundle with optimized core alignment. This preliminary structuring allows for efficient coupling of partitioned high NA pump light from multiple sources into the signal fiber, establishing proper optical paths before energy-intensive operation begins.
Solution Approach 2:
The patent employs a composite fused fiber bundle structure where cladless pump fiber cores are integrated with the signal fiber core in a unified assembly. This composite architecture enables efficient energy transfer from partitioned pump sources by directly coupling pump modes to signal modes within the fused structure, overcoming the energy loss limitations of conventional tapered bundles.
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 increased pump energy transfer and power output, reduces fiber failure risks by introducing high NA pump light within the lasing cavity, and improves manufacturing flexibility by allowing more pump fibers to be combined, resulting in enhanced performance and efficiency of optical fiber-based gain systems.
Implementation Method 1
The capillary tube is collapsed onto the bundled coreless optical fibers, fusing them together
Data Source
AI summary
As kilowatt class fiber laser and amplifier systems become more in demand, there are ongoing efforts to improve optical fiber laser and amplifier designs to maximize efficiency and further increase the capacity of these high-energy optical fiber lasers and amplifiers. The present disclosure provides a fiber laser or amplifier system configured to efficiently and conveniently generate and couple high numerical aperture and high-energy pump light into a fiber laser or amplifier system.