Capillary Tube Cladding Light Stripper for Back-Reflected Laser Light
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Solution Overview
Problem
In high-power fiber lasers used for material processing, back-reflected light can cause damage to bonding materials and internal components due to absorption or transmission through capillary tubes, and existing solutions do not adequately manage thermal stress during high-energy events like cutting or welding.
Innovation Solution
A capillary tube with a cladding light stripper feature, such as transverse grooves or a roughened surface, to scatter back-reflected light and prevent damage, combined with a thermal path optimized optical signal combiner housing that uses materials with closely matched thermal expansion coefficients and a heat management system to dissipate energy effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a capillary tube is used to enclose input fibers in a combiner, then the combiner can efficiently combine pump light from multiple fibers, but back-reflected light can damage bonding materials and internal components through absorption or transmission
Solution Approach 1:
The patent converts the harmful back-reflected light into a useful function by using it to heat and evaporate bonding material in a controlled manner. The cladding light stripper captures back-reflected light that would otherwise damage components, and the controlled thermal path directs this energy to evaporate bonding material at the capillary tube exit, transforming a harmful factor into a beneficial cleaning function.
Solution Approach 2:
The patent introduces bonding material as an intermediary substance between the capillary tube and the components it protects. This bonding material absorbs the energy from back-reflected light through controlled thermal conduction, preventing direct damage to internal components while allowing the energy to be safely dissipated through controlled evaporation.
2Strength
If bonding material is used to secure the capillary tube, then the capillary tube can be securely mounted in the combiner housing, but back-reflected light can cause the bonding material to overheat and fail
Solution Approach 1:
The patent changes the thermal parameters of the bonding material by selecting materials with specific thermal conductivity and melting/evaporation points. The bonding material is chosen to have thermal properties that allow it to withstand the heat from back-reflected light without failing, while still providing secure mechanical mounting of the capillary tube.
Solution Approach 2:
The patent considers thermal expansion characteristics of the bonding material and capillary tube materials to ensure they expand and contract compatibly under thermal stress. This prevents mechanical failure of the mounting structure while allowing the bonding material to survive the thermal environment created by back-reflected light.
3Productivity
If high-power laser processing is performed, then material cutting or welding efficiency is improved, but thermal stress on the combiner housing increases during high-energy events
Solution Approach 1:
The patent extracts the thermal management function from the combiner housing design by incorporating a dedicated controlled thermal path system. This separate thermal management pathway allows the housing to maintain structural integrity under high thermal stress while enabling efficient heat dissipation during high-power laser processing operations.
Solution Approach 2:
The patent employs composite material strategies in the combiner housing design, combining materials with different thermal and mechanical properties. This allows the housing to simultaneously provide mechanical support, manage thermal stress, and facilitate controlled heat dissipation during high-power laser processing.
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
Prevents damage to bonding materials and internal components by scattering back-reflected light and effectively manages thermal stress through controlled heat dissipation, ensuring consistent performance during high-energy events.
Implementation Method 1
a cladding light stripper to scatter back-reflected light traveling through the capillary tube
Implementation Method 2
The light stripping feature may be provided by a roughened surface on the capillary tube
Implementation Method 3
a thermal path optimized optical signal combiner housing that uses materials with closely matched thermal expansion coefficients and a heat management system to dissipate energy effectively
Data Source
AI summary
Some embodiments may include a fiber laser including two or more input fibers and an output fiber to deliver a beam to a workpiece, the fiber laser comprising. The fiber laser may include a combiner having ends and a length, wherein the combiner is arranged to release, from its length, a portion of back-reflected light received from the output fiber at an output end of the ends from the combiner, the combiner including: a capillary tube to enclose part of the two or more input fibers at an input end of the ends of the combiner, the capillary tube having ends and a length located between the ends of the capillary tube; and a cladding light stripper (CLS) defined by part of the length of the capillary tube, wherein the CLS provides the release of the portion of the back-reflected light. Other embodiments may be disclosed and/or claimed.