Hollow-Core Photonic Crystal Fiber Sensor for Sulfuric Acid Detection

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Solution Overview

Problem

Existing optical sensors for sulfuric acid detection in industrial applications face challenges in accurately determining varying concentrations due to impractical constant refractive index assumptions and complex structures, limiting their sensitivity and practicality in laboratory production.

Innovation Solution

A photonic crystal fiber (PCF) based optical sensor with a hollow core, inner cladding section, and outer layer, utilizing fused silica and circular-shaped channels, is designed to measure sulfuric acid concentration by exposing a composition to laser light and detecting propagated light through an optical coupler, achieving high sensitivity and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hybrid core fused silica-based chemical sensor with different shaped air holes is used, then sulfuric acid detection capability is achieved, but manufacturing complexity increases and laboratory production becomes challenging

Engineering Contradiction:

Improvesulfuric acid detection capabilityVSAvoidlaboratory production feasibility

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs uniform circular-shaped air holes in the cladding section instead of different shaped air holes, creating a homogeneous structure that maintains sulfuric acid detection capability while significantly simplifying the manufacturing process and enabling laboratory production

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The sensor uses a composite structure combining fused silica cladding material with circular air holes and a hollow core, achieving effective sulfuric acid detection through the interaction of these materials while maintaining manufacturing feasibility

Inventive Principle:

Principle #40Composite materials

2Device complexity

If a constant refractive index is used through all terahertz bands, then sensor design is simplified, but sensing accuracy deteriorates due to impractical assumptions

Engineering Contradiction:

Improvesensor design complexityVSAvoidsensing accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent incorporates wavelength-dependent refractive index variations in the terahertz bands into the sensor design, using the actual varying refractive index of sulfuric acid across different wavelengths to achieve accurate sensing while accounting for the complex dispersion characteristics of the analyte

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional hollow core PCF-based alcohol sensor structure is used, then sensitivity of 89% is achieved, but the structure cannot be effectively adapted for sulfuric acid detection with varying concentrations

Engineering Contradiction:

ImprovesensitivityVSAvoidconcentration detection range

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent designs a universal PCF-based sensor structure with circular air holes and hollow core that can detect various analytes including sulfuric acid at different concentrations, extending the applicability beyond alcohol detection while maintaining high sensitivity through the adaptable optical path design

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 sensor achieves a sensitivity of 88% to 98% for sulfuric acid concentrations from 5% to 45% with low confinement loss and single-mode propagation, providing accurate concentration measurements.

Implementation Method 1

various waveguides, such as dielectric waveguides, parallel-plate waveguides, metallic waveguides, and Bragg fibers, are used to guide electromagnetic waves from a source to a destination

Methodology Applied

Scientific EffectOptical waveguide: Waveguide (optics)

Implementation Method 2

a second end of the PCF is in optical communication with the optical coupler

Methodology Applied

Scientific EffectOptical detection: Photoelectric Effect

Data Source

PatentUS12422358B2Optical sensor and method of fabricating the optical sensor

Publication Date: 2025.09.23 KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS

AI summary

An optical sensor that includes a photonic crystal fiber (PCF) and an optical coupler. The PCF includes a hollow core with a first diameter (Dc), an inner cladding section, and an outer layer surrounding the inner cladding section. The inner cladding section includes a cladding material and a plurality of spaced apart circular-shaped channels disposed in the cladding material surrounding the hollow core. The cladding material includes at least one of glass, ceramic, and glass-ceramic. Each spaced apart circular-shaped channel has substantially the same size and an average diameter (d). A first end of the PCF is in optical communication with a light source and a second end of the PCF is in optical communication with the optical coupler.