Optical Fiber Grating via Mechanical Radial Compression

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Solution Overview

Problem

Existing methods for manufacturing optical fibre gratings are costly and have low yield due to the use of expensive equipment and complex processes.

Innovation Solution

The method involves arranging hard embedding bodies at intervals along the axis of the optical fibre core to change the density alternately, which in turn changes the refractive index, forming the grating through a simple and cost-effective physical process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If ultraviolet light exposure is used to write the grating into the fibre core, then the refractive index periodically changes to form a permanent space phase grating, but the manufacturing cost increases and yield decreases

Engineering Contradiction:
Improverefractive index modulation precisionVSAvoidmanufacturing yield
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces the optical writing system (ultraviolet light exposure) with a mechanical system that applies periodic radial compression forces to the fibre. This mechanical approach creates density variations in the fibre core that result in refractive index modulation, achieving the same grating formation function through mechanical means instead of optical means, thereby reducing equipment cost and improving manufacturing yield

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical parameter used to create refractive index modulation from optical exposure (energy input) to mechanical compression (pressure application). By applying periodic radial compression forces during fibre drawing, the fibre density varies periodically, which directly modulates the refractive index through the density-refractive index relationship, achieving grating formation without expensive UV writing equipment

Inventive Principle:
Principle #35Parameter changes

2Reliability

If expensive writing device is used for ultraviolet light exposure, then permanent space phase grating can be formed, but the manufacturing cost increases

Engineering Contradiction:
Improvegrating stabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent substitutes the expensive optical writing device with a simple mechanical compression system. The periodic radial compression is applied through mechanical means during fibre drawing, creating the necessary density variations without requiring ultraviolet light sources, photomasks, or other costly optical components, while still achieving stable and permanent grating structures

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs simple, inexpensive mechanical components for applying compression forces rather than expensive, complex optical writing systems. The mechanical compression apparatus can be easily fabricated and replaced, making the manufacturing process more cost-effective while maintaining grating reliability

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 results in a high-efficiency, low-cost production process that improves the filtering properties of the optical fibre grating by periodically changing the refractive index, making the manufacturing process simpler and more productive.

Implementation Method 1

the density of the optical fibre core changes in an alternate manner along the axial direction of the optical fibre core; the refractive index of the optical fibre core changes in the axial direction to form the optical fibre grating

Methodology Applied
Scientific EffectDensity change:

Implementation Method 2

thereby reflecting or transmitting light waves with a specific wavelength; light waves with the remaining wavelengths are not affected, but are continuously transmitted along the fibre grating

Methodology Applied
Scientific EffectLight reflection and transmission: Reflection

Implementation Method 3

the refractive index of the fibre core periodically changes along the axial direction to form a permanent space phase grating

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3540483B1Manufacturing method of optic fiber grating
Publication Date: 2023.12.13 FIBERHOME TELECOMMUNICATION TECHNOLOGIES CO LTD
  • EP3540483B1 patent drawingFigure 1~2
  • EP3540483B1 patent drawingFigure 3~4

AI summary

An optical fiber grating, comprising an optical fiber core (1), an optical fiber coating layer (2) and an optical fiber colored layer (3) in sequence from inside to outside. The optical fiber core (1) comprises a plurality of high-density segments and a plurality of low-density segments. The high-density segments and the low-density segments are alternately provided in the axial direction of the optical fiber core. A plurality of hard embedded bodies (4) are provided between the optical fiber coating layer (2) and the optical fiber colored layer (3). The hard-embedded bodies (4) circumferentially cald the optical fiber coating (2) and the optical fiber core (1). The plurality of embedded bodies (4) are arranged at intervals in the axial direction of the fiber core (1). The density of parts of the optical fiber core (1) that are cladded by the hard-embedded bodies (4) is greater than the density of the other parts of the optical fiber core (1) that are not cladded by the hard-embedded bodies (4). The manufacturing process of the optical fiber grating is simple, the cost is low, and the production efficiency is high.