Optical Fiber Mode Switching for Flexible Laser Beam Profiles
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Solution Overview
Problem
Existing laser processing technologies face challenges in efficiently changing the laser beam profile without adjusting optics, maintaining annular beams away from focus, and optimizing beam parameters for diverse material processing tasks, leading to inefficiencies and suboptimal results in cutting, welding, and additive manufacturing.
Innovation Solution
A method and apparatus using a coupler to switch laser radiation between different optical modes, combined with a squeezing mechanism and optical fiber configurations, to dynamically control the beam profile, allowing for flexible adjustment of spot size and divergence without mechanical adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If external optics are used to change beam profile from Gaussian to top hat or annular, then beam profile flexibility is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical/optical adjustment systems with an electrical control system. By applying voltage to the optical fiber, the laser beam profile can be dynamically changed from Gaussian to top-hat or annular profiles without any external optics or mechanical adjustments. This substitution of electrical control for mechanical/optical systems resolves the contradiction by achieving beam profile flexibility while reducing device complexity.
Solution Approach 2:
The patent changes the electrical parameter (voltage applied to the optical fiber) to control the laser beam profile. By varying the voltage, the beam profile transitions between different modes (Gaussian, top-hat, annular) and the spot size can be adjusted. This parameter change approach enables beam profile flexibility without adding complex optical components.
2Manufacturing precision
If working distance is adjusted to change spot size, then spot size control is improved, but processing time increases
Solution Approach 1:
The patent replaces the mechanical adjustment of working distance with an electrical control mechanism. By applying voltage to the optical fiber, the spot size can be changed instantaneously without moving any components or adjusting the working distance. This substitution enables precise spot size control while maintaining high processing speed, resolving the contradiction between manufacturing precision and productivity.
3Manufacturing precision
If fundamental Gaussian mode is used for additive manufacturing, then feature size precision is improved, but building speed decreases
Solution Approach 1:
The patent changes the laser beam mode parameter by applying voltage to the optical fiber. This enables transition from fundamental Gaussian mode (small spot size for precise features) to higher-order modes with larger, more uniform spot sizes (faster processing). The parameter change approach allows dynamic adaptation between precision and speed requirements during additive manufacturing, resolving the contradiction between feature size precision and building speed.
4Object-affected harmful factors
If annular laser beam is used for drilling, then surface damage is reduced, but beam divergence increases
Solution Approach 1:
The patent replaces traditional annular beam generation methods (axicon lenses, cladding structures) with an electrical control approach. By applying voltage to the optical fiber, an annular beam profile is generated with inherently lower divergence compared to conventional methods. This substitution achieves surface damage reduction while maintaining beam stability and low divergence, resolving the contradiction between harmful factors and beam composition stability.
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
Enables faster processing speeds, improved edge quality, and optimized beam parameters for various materials by converting the near-field laser profile to a far-field distribution, reducing the need for mechanical adjustments and enhancing processing capabilities.
Implementation Method 1
an optical fibre in which laser radiation is able to propagate along the optical fibre in a first optical mode having a first mode order, a second optical mode having a second mode order, and a third optical mode having a third mode order
Implementation Method 2
the coupler is configured to switch laser radiation propagating in the first optical mode to the laser radiation propagating in the second order mode; and the coupler is configured to switch the laser radiation propagating in the second optical mode to laser radiation propagating in the third order mode
Data Source
Figure 1
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AI summary
Apparatus for laser processing a material (11), which apparatus comprises a laser (1), an optical fibre (2), and a coupler (125), wherein: the laser (1) is connected to the optical fibre (2); the optical fibre (2) is such that laser radiation (13) is able to propagate along the optical fibre (2) in a first optical mode (21) having a first mode order (24), a second optical mode (22) having a second mode order (25), and a third optical mode (23) having a third mode order (26); the third mode order (26) is higher than the second mode order (25); and the second mode order (25) is higher than the first mode order (24); the apparatus being characterized in that: the coupler (125) is configured to switch laser radiation propagating in the first optical mode (21) to the laser radiation propagating in the second order mode (22); and the coupler (125) is configured to switch the laser radiation propagating in the second optical mode (22) to laser radiation propagating in the third order mode (23).