Non-tapered High NA Pump Combiner for Fiber Laser Systems
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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 potential for fiber failure due to the architecture of tapered fiber bundles and glass-clad pump fibers.
Innovation Solution
A novel non-tapered high NA pump and signal combiner architecture that allows for the coupling of partitioned high NA pump light outside the lasing cavity, using a fat-fiber adapter and cladless inputs to increase pump energy and efficiency, while reducing fiber failure risks by introducing pump light within the lasing cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional tapered fiber bundle architecture is used, then pump light coupling is simplified, but power output is restricted and fiber failure risk increases
Solution Approach 1:
The pump light coupling is divided into two independent stages: first combining multiple pump sources into a single high-NA pump beam using a non-tapered pump combiner, then coupling this combined pump light into the gain fiber. This segmentation allows optimization of each stage independently, enabling high power output while maintaining reliability through reduced fiber stress.
Solution Approach 2:
A non-tapered pump combiner acts as an intermediary device between multiple pump sources and the gain fiber. This combiner with cladless inputs and high numerical aperture design efficiently combines pump light without requiring tapered fiber bundles, thereby increasing power capacity while reducing fiber failure risk associated with conventional tapered architectures.
2Use of energy by moving object
If glass-clad pump fibers are used, then fiber protection is improved, but pump light coupling efficiency decreases
Solution Approach 1:
The cladding is removed from the pump fibers at the input end of the combiner, creating cladless inputs. This extraction of the protective cladding layer allows direct coupling of high-NA pump light into the fiber cores without the efficiency losses associated with glass-clad interfaces, while the combiner structure itself provides the necessary protection and support.
Solution Approach 2:
The numerical aperture of the pump combiner is increased to high values through the non-tapered design with cladless inputs. This parameter change in NA enables more efficient coupling of high-NA pump light sources while maintaining structural integrity and protection through the combiner architecture.
3Ease of manufacture
If tapered fiber bundles are used for pump coupling, then alignment is simplified, but manufacturing flexibility is reduced
Solution Approach 1:
Instead of tapering the fibers to achieve coupling (conventional approach), this invention uses non-tapered fibers with cladless inputs. The inversion of the conventional tapered design allows standard manufacturing techniques to be used while achieving the desired coupling efficiency and maintaining flexibility for manufacturing and upgrading.
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 solution enhances the power output and efficiency of optical-fiber-based gain systems by efficiently coupling high NA pump light, reducing pump loss, and increasing the flexibility in manufacturing and upgrading, while minimizing fiber failure risks.
Implementation Method 1
allows for coupling of partitioned high numerical aperture (NA) pump light outside a lasing cavity
Implementation Method 2
using a fat-fiber adapter and cladless inputs to increase pump energy and efficiency, while reducing fiber failure risks
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.