Optical Fiber Laser Welding in Perforated Elements Without Beam Loss
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Solution Overview
Problem
Existing methods for welding optical fibers to perforated elements, such as CO2 splicing, adhesive bonding, and bracing, often damage the sensitive kagome structure, pose alignment challenges, and fail to maintain beam quality and gas-tightness, especially for hollow core fibers.
Innovation Solution
A pulsed laser beam welding method where the laser focus is moved axially along the cylindrical joining surface to create a narrow, precise weld seam, using ultrashort pulse laser beams to locally melt the materials and form a stable connection without damaging the fiber's inner structure, allowing for precise positioning and maintaining beam quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If CO2 splicing is used to weld optical fibers to perforated elements, then connection strength is improved, but the sensitive kagome structure is melted and beam quality deteriorates
Solution Approach 1:
The patent changes the welding parameters by using ultrashort pulse laser beams with pulse durations of less than 500 ps instead of continuous CO2 laser beams. This parameter change enables localized heating that melts only the necessary connection regions without damaging the sensitive kagome structure, thus maintaining beam quality while achieving strong connections
Solution Approach 2:
The patent employs periodic pulsed laser action instead of continuous laser heating. The ultrashort pulses deliver energy in discrete time intervals, allowing heat to be confined to specific regions and preventing thermal diffusion that would damage the kagome structure. This periodic action enables strong welding while preserving beam quality
2Ease of operation
If adhesive bonding or O-ring bracing is used for connection, then alignment flexibility is improved, but strain problems occur and gas-tightness is compromised
Solution Approach 1:
The patent replaces mechanical connection methods (adhesive bonding and O-ring bracing) with laser-induced material fusion. The ultrashort pulse laser melts and fuses the fiber cladding and perforated element material directly, creating a monolithic connection that provides both alignment flexibility and reliable gas-tightness without the strain problems associated with mechanical methods
3Manufacturing precision
If high precision mounting with multiple degrees of freedom is used, then welding success is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by concentrating the welding action at the precise interface between fiber and perforated element using focused ultrashort pulse laser beams. The laser focus is positioned exactly at the joining surface, enabling successful welding with minimal alignment requirements and reducing the need for complex mounting adjustments
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 method achieves strong, gas-tight connections with minimal thermal stress, enabling the handling of hollow core fibers for further fabrication while preserving beam quality and allowing for the use of fibers with different thermal properties.
Implementation Method 1
a pulsed laser beam is focused onto a region of a joining surface... the pulsed laser beam is a USP laser beam that includes laser radiation having pulse durations of less than 500 ps... to locally melt the materials
Implementation Method 2
the laser focus in the region of the joining surface is moved... to produce at least one weld seam
Data Source
AI summary
Methods, devices, and systems for welding optical fibers and perforated elements by pulsed laser beam are provided. In one aspect, a method includes focusing a pulsed laser beam onto a region of a joining surface formed by an outer circumference of an optical fiber and an inner circumference of a hole of a perforated element, a beam direction of the pulsed laser beam running in an axial direction of the joining surface, and moving a laser focus of the pulsed laser beam in the region axially in or counter to the beam direction to produce at least one weld seam in the region. The optical fiber and the perforated element are locally melted in the region by the pulsed laser beam focused into a material of the optical fiber and a material of the perforated element and are thereby welded to one another.