Twisted Optical Fiber Core for Annular Beam Generation

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Solution Overview

Problem

Conventional methods for generating optical beams with annular shapes in optical fibers require expensive and alignment-sensitive free-space optics, leading to poor beam quality and undesirable processing outcomes in material processing applications.

Innovation Solution

An optical fiber device with a unitary core that twists along its length, creating a rotary optical beam with an annular shape without the need for free-space optics, by varying the refractive index structure and incorporating a secondary section offset from the core center, which converts non-rotary optical beams into rotary guided modes or leaky waves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If free-space optics are used to generate annular optical beams, then annular beam shape can be achieved, but device complexity and cost increase

Engineering Contradiction:

Improvebeam shapeVSAvoiddevice complexity

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The patent replaces free-space optical components (mechanical/optical system) with a fiber-based solution where the annular beam is generated directly within the optical fiber through refractive index engineering. The unitary core with offset secondary section creates the annular beam shape through refractive effects, eliminating the need for external optical elements like axicons or spiral phase plates.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent modifies the refractive index parameters of the optical fiber core by introducing a secondary section with a different refractive index offset from the center. This parameter change enables the fiber to transform ordinary optical beams into rotary guided modes that propagate as annular beams, achieving beam shaping through material property modification rather than mechanical component arrangement.

Inventive Principle:

Principle #35Parameter changes

2Shape

If free-space optics are used to generate annular optical beams, then annular beam shape can be achieved, but alignment sensitivity increases

Engineering Contradiction:

Improvebeam shapeVSAvoidalignment sensitivity

Core Design Contradiction:

ShapeVSEase of operation

Solution Approach 1:

The patent merges the beam shaping function with the optical fiber structure itself. The unitary core with offset secondary section is integrated directly into the fiber, combining the waveguide function with the beam shaping function. This eliminates the need for separate optical components that would require precise alignment, as the shaping is inherently built into the fiber's refractive index profile.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If conventional fiber methods are used, then device simplicity is maintained, but beam quality deteriorates

Engineering Contradiction:

Improvedevice simplicityVSAvoidbeam quality

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent introduces local quality variation within the fiber core by creating a secondary section with a specific refractive index offset from the center. This localized modification of the refractive index profile enables the generation of high-quality annular beams with sharp edges, improving beam quality without requiring complex overall device structure.

Inventive Principle:

Principle #3Local quality

4Productivity

If rotary optical beams are generated directly in fiber, then processing performance improves, but fiber structure complexity increases

Engineering Contradiction:

Improveprocessing performanceVSAvoidfiber structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the fiber core into a primary section and a secondary section with different refractive indices. This segmentation allows the fiber to function as both a waveguide and a beam-shaping element, generating rotary guided modes that produce high-quality annular beams for improved material processing while keeping the overall structure relatively simple.

Inventive Principle:

Principle #1Segmentation

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 approach enables the generation of high-quality annular beam profiles with sharp edges, suitable for improved material processing, such as metal cutting, directly within the optical fiber, eliminating the need for bulky free-space optics and enhancing processing performance.

Implementation Method 1

a refractive index of the primary section is greater than a refractive index of the secondary section; and the unitary core twists about an optical axis of the optical fiber device along a length of the optical fiber device

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS11347069B2Rotary optical beam generator

Publication Date: 2022.05.31 WELLS FARGO BANK NA

AI summary

An optical fiber device may include a core including a primary section and a secondary section. The secondary section may include at least one insert element inserted within the primary section at an off-center location with respect to a center of the primary section. The secondary section may twist about an axis of the optical fiber device along a length of the optical fiber device. A rate of twist at which the secondary section twists about the axis may increase from a first end of the optical fiber device toward a second end of the optical fiber device. The secondary section being twisted about the axis may cause an optical beam, launched at the first end of the optical fiber device, to be at least partially converted to a rotary optical beam at the second end of the optical fiber device.