Hollow Core Fiber Surface Mode Suppression
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Solution Overview
Problem
Hollow core photonic crystal fibers often suffer from surface modes that introduce noise, increase attenuation, and alter dispersion properties, which are undesirable in applications like optical communications and sensors.
Innovation Solution
Incorporating relatively small resonant features in the cladding that suppress surface modes by efficiently coupling light into these features, either through leakage or absorption, thereby reducing or eliminating surface modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hollow core photonic crystal fibers are used to guide light in the core, then light guidance is achieved, but surface modes are generated that introduce noise and increase attenuation
Solution Approach 1:
The patent extracts and removes surface modes from the fiber system by designing the cladding structure to selectively eliminate these harmful modes while preserving the fundamental core mode. This is achieved by modifying the cladding hole geometry and arrangement to create a photonic bandgap that excludes surface mode propagation.
Solution Approach 2:
The patent applies local quality by creating non-uniform cladding structures with varying hole sizes, shapes, and spacing in different regions. The cladding is designed with specific local variations that target surface mode suppression while maintaining overall light guidance functionality.
2Adaptability or versatility
If surface modes are present in hollow core fibers, then certain modes can be supported, but noise and attenuation increase
Solution Approach 1:
The patent extracts harmful surface modes from the supported mode set by designing the cladding photonic bandgap to exclude these modes. This selective extraction allows only desirable fundamental modes to propagate while removing surface modes that cause attenuation and noise.
Solution Approach 2:
The patent changes cladding structural parameters such as hole diameter, spacing, and arrangement to modify the photonic bandgap characteristics. These parameter adjustments are optimized to suppress surface modes while maintaining acceptable mode support for the intended application.
3Ease of manufacture
If conventional cladding structures are used, then manufacturing is simpler, but surface modes cannot be effectively suppressed
Solution Approach 1:
The patent implements local quality through non-uniform cladding designs with varying hole geometries that can be fabricated using standard capillary tube stacking methods. The local variations in hole size and spacing are achieved by selecting appropriate capillary tubes during the stacking process, maintaining manufacturing feasibility while enabling surface mode suppression.
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 effectively suppresses surface modes by up to 20 dB/m, improving the optical properties of the fibers by reducing noise and attenuation, making them suitable for applications requiring low loss and high precision.
Implementation Method 1
suppress surface modes by efficiently coupling light into these features, either through leakage or absorption
Implementation Method 2
suppress surface modes by efficiently coupling light into these features, either through leakage or absorption
Implementation Method 3
The PBG may be realized by arranging the microstructured cladding in a manner, whereby it comprises a periodic modulation of the refractive index
Data Source
AI summary
The invention relates to a hollow core optical fiber having light guided in a single-mode in the core.