All-Fiber Laser Combiner Tapered Design
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Solution Overview
Problem
Current fiber-based laser combiners face challenges in achieving high packing density of cores, leading to reduced brightness and increased costs due to the use of bulk optical lenses and mechanical systems, which are not suitable for high-power applications, and there is a need for an all-fiber approach that can efficiently combine or split optical power with tight core spacing.
Innovation Solution
An all-fiber laser combiner with a two-section tapered design, where the first section comprises a bundle of single or few-mode fibers with a high taper ratio to maintain low NA and prevent mode interactions, coupled to an output fiber, and the second section further reduces the beam size using multimode fibers with added cladding, allowing for high optical density and efficient power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple singlemode fibers are bundled together with low packing density, then the device is easier to manufacture and operate, but the brightness of the optical source is significantly reduced when coupled into the common output fiber
Solution Approach 1:
The patent implements nesting by placing multiple fiber cores within a shared cladding structure, where inner cores are surrounded by outer cores. This nested arrangement increases packing density while maintaining manufacturability, directly resolving the contradiction between ease of manufacture and brightness by enabling tighter core spacing without requiring complex external alignment mechanisms
Solution Approach 2:
The patent transitions from a planar 2D arrangement of fiber bundles to a 3D nested configuration where cores are arranged in multiple radial layers within a common cladding. This dimensional change allows significantly higher packing density (increasing brightness) while maintaining a simple overall structure that is easy to manufacture as a sealed unit device
2Stability of the object's composition
If fiber cores are spaced far apart in a bundle, then mode interactions are prevented, but the packing density is very low and brightness is reduced
Solution Approach 1:
The patent applies local quality by providing different cladding structures for different regions: outer cladding surrounds each individual core to prevent mode interactions locally, while inner cladding provides additional isolation between adjacent cores. This localized approach allows cores to be spaced closer together (increasing packing density) while maintaining mode isolation through the distributed cladding structure
Solution Approach 2:
The patent introduces cladding material as an intermediary substance between adjacent fiber cores. This cladding acts as a optical barrier that prevents mode coupling and interactions, enabling the cores to be positioned closer together for higher packing density without sacrificing mode isolation. The cladding mediates between the conflicting requirements of close spacing and mode separation
3Ease of operation
If bulk optical lenses and mechanical systems are used for beam combining, then alignment and steering are achieved, but the device complexity increases and maintenance costs increase for high power applications
Solution Approach 1:
The patent replaces mechanical beam steering and alignment systems with an all-fiber integrated design where light propagation is controlled through optical waveguide principles. The fiber optic structure inherently guides and combines beams without requiring external mechanical lenses, mirrors, or adjustment mechanisms, thereby reducing device complexity and eliminating maintenance issues associated with mechanical systems in high-power environments
Solution Approach 2:
The patent merges multiple functions (beam combining, alignment, and steering) into a single integrated fiber optic structure. Instead of using separate bulk optical components and mechanical systems, the invention combines these functions at the fiber level through carefully designed core arrangements and cladding structures, simplifying the overall device while maintaining operational effectiveness
4Quantity of substance
If fiber tapering is used to reduce separation between cores, then packing density increases, but optical power leaks out of the core or couples into adjacent cores at high taper ratios
Solution Approach 1:
The patent segments the cladding structure into multiple functional layers: outer cladding that maintains structural integrity and provides primary mode confinement, and inner cladding that provides additional optical isolation between cores. This segmentation allows the fiber to be tapered to high ratios (increasing packing density) while the distributed cladding structure maintains reliable power confinement by preventing mode coupling even at reduced core separations
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 solution achieves a high brightness source with a high taper ratio, enabling efficient power combination and splitting, reducing maintenance costs and enabling applications that require tight core spacing, such as high-power cutting and medical treatments, while maintaining low NA and preventing mode interactions.
Implementation Method 1
a first tapered section comprises a bundle of input fibers, preferably single or few mode fibers, bundled together
Implementation Method 2
maintaining a low NA along the length of the first tapered section
Implementation Method 3
preventing interaction between modes of the separate cores as well as preventing interaction between the modes and the outer boundary of any cladding surrounding the cores
Implementation Method 4
all-fiber devices that combine optical laser power from multiple separate sources such as lasers or amplifiers
Data Source
AI summary
Embodiments of the present invention generally relate to laser combiners, and more specifically, to all-fiber devices that combine optical laser power from multiple separate sources such as lasers or amplifiers. In one embodiment, a method of manufacturing a combiner device comprises: positioning an plurality of fibers into a bundle of fibers; drawing the bundle of fibers to create a tapered section, the tapered section having a first outer diameter at an input end, a second outer diameter at an output end, and a taper ratio of at least three; wherein at least one of the fibers of the bundle of fibers comprises an optical waveguide configured for propagating an optical mode from the input end to the output end, and wherein a mode field diameter of the optical mode at the input end is substantially the same as the mode field diameter at the output end.