Sealed Hollow Core Fiber Array Launcher for Clean Beam Combining
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Solution Overview
Problem
Conventional single mode and large mode area fiber technologies are limited by nonlinear effects at high optical power levels, leading to size and weight constraints in directed energy systems, while hollow core fibers face contamination and alignment issues at the fiber end, affecting beam quality and reliability.
Innovation Solution
A hollow core optical fiber array launcher assembly with sealed channels and a lens array is used to align and focus beams precisely, minimizing contamination and ensuring consistent wavefronts, suitable for coherent and spectral beam combining systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hollow core fiber end is left open to environment, then beam quality is improved with flat wave front, but contamination occurs causing thermal destruction
Solution Approach 1:
An anti-reflection coated window is introduced as an intermediary component between the hollow core fiber and the external environment. This window seals the fiber end while maintaining optical transparency, thus preventing contamination without significantly degrading beam quality. The anti-reflection coating minimizes optical losses at the interface.
Solution Approach 2:
The hollow core fiber end is sealed with a window that creates a protected environment, effectively replacing the open exposure to contaminating atmosphere with a sealed, inert barrier that prevents harmful substances from entering the fiber core.
2Reliability
If hollow core fiber is sealed with fused silica end cap, then contamination is eliminated, but manufacturing precision deteriorates due to length uncertainty
Solution Approach 1:
A precisely manufactured window component serves as an intermediary that can be consistently positioned relative to the fiber end. This standardized interface component enables repeatable assembly with consistent wave front characteristics, unlike variable-length end caps.
Solution Approach 2:
The window is pre-coated with anti-reflection coating during manufacturing, and its thickness and optical properties are predetermined and controlled. This preliminary preparation ensures consistent optical performance across multiple assemblies without requiring post-assembly adjustments.
3Device complexity
If conventional fiber technology is used, then device complexity is reduced, but power delivery capability deteriorates due to nonlinear effects at high power levels
Solution Approach 1:
The fundamental parameter of the light guiding medium is changed from solid glass (conventional fiber) to air (hollow core fiber). This parameter change eliminates nonlinear optical effects that limit power delivery in conventional fibers, enabling high-power beam transmission despite increased system complexity.
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 assembly provides high beam quality and power output by maintaining precise fiber orientation and sealing, overcoming nonlinear effects and contamination issues, enabling efficient beam delivery in directed energy systems.
Implementation Method 1
Hollow core fibers guide the optical mode based on photonic bandgap principles, instead of index of refraction gradient
Implementation Method 2
a lens array including a plurality of lenses positioned so that one of the lenses in the array receives the beam in each channel
Data Source
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AI summary
A beam combiner array assembly including an array block having a back wall and a front surface and a plurality of aligned and sealed channels extending from the back wall to the front surface. A lens array including a plurality of lenses is secured to the front surface of the block so that one of the lenses is aligned with each channel, and a plurality of fiber flanges are secured to the back wall of the block so that a separate one of the flanges is aligned with each channel. A hollow core fiber extends through each flange and the back wall so that an end of the fiber is positioned within one of the channels. A beam that propagates down each fiber is emitted into the channel, focused by the lens and emitted from the assembly as a collimated beam.