Ceramic Core Waveguide for Low-Loss Terahertz Transmission

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Solution Overview

Problem

Current terahertz waveguides face challenges in achieving low loss and mechanical robustness due to high-frequency signal absorption and dispersion, particularly in the sub-mm wave range, with existing materials like metals and plastics being insufficient for long-distance transmission.

Innovation Solution

The development of ultra-high purity alumina ceramic waveguides with a thin form factor and high dielectric constant, combined with a cladding layer, to minimize transmission loss and enhance mechanical strength, enabling efficient propagation of terahertz signals over extended periods and varied environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional metallic waveguides are used for THz transmission, then mechanical robustness is improved, but transmission loss increases due to high-frequency signal absorption

Engineering Contradiction:

Improvemechanical robustnessVSAvoidtransmission loss

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The waveguide uses a composite structure with a ceramic core (alumina or silica) surrounded by a polymer cladding layer. The ceramic core provides mechanical strength and low THz loss, while the polymer cladding enables flexibility and additional protection. This composite approach resolves the contradiction by combining materials with complementary properties that neither material alone could provide.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If plastic waveguides are used for THz transmission, then flexibility is improved, but transmission loss increases due to material absorption and dispersion

Engineering Contradiction:

ImproveflexibilityVSAvoidtransmission loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The polymer cladding is specifically selected to have low dielectric loss and low dispersion in the THz range, while the ceramic core provides the primary transmission path with minimal loss. The cladding thickness is optimized to provide flexibility without significantly increasing transmission loss, resolving the contradiction between flexibility and transmission quality.

Inventive Principle:

Principle #40Composite materials

3Loss of energy

If ceramic waveguides are used for THz transmission, then transmission loss is reduced, but mechanical robustness worsens due to fragility

Engineering Contradiction:

Improvetransmission lossVSAvoidmechanical robustness

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The thin ceramic core (50-200 micrometers thick) provides low-loss THz transmission, while the surrounding polymer cladding layer (100-500 micrometers thick) provides mechanical protection and flexibility. The cladding acts as a protective jacket that prevents the fragile ceramic from breaking while maintaining the low-loss transmission characteristics of the ceramic core.

Inventive Principle:

Principle #40Composite materials

4Loss of energy

If rectangular rod waveguides are used for THz transmission, then low loss is achieved, but flexibility is reduced due to thickness

Engineering Contradiction:

Improvetransmission lossVSAvoidflexibility

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The waveguide uses a thin ribbon geometry instead of a thick rectangular rod, with the ceramic core thickness reduced to 50-200 micrometers. This thin-film approach maintains low transmission loss while enabling the waveguide to be flexible and bendable. The polymer cladding further enhances flexibility by providing a compliant outer layer that can accommodate bending without breaking the fragile ceramic core.

Inventive Principle:

Principle #30Flexible shells and thin films

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 provides a low-loss, mechanically robust terahertz waveguide capable of handling high-frequency signals over long distances with reduced transmission loss and improved flexibility, addressing the limitations of traditional waveguides.

Implementation Method 1

Terahertz (THz) waveguides can be formed from a guiding structure in which the real part of the dielectric constant is higher than that of the surrounding material or space. Such waveguides can be used to confine and transport a THz optical signal

Methodology Applied

Scientific EffectDielectric confinement: Dielectric Permittivity

Implementation Method 2

a cladding disposed around the ceramic core, the cladding having a dielectric constant (Dk2) such that Dk2<Dk1

Methodology Applied

Scientific EffectDielectric shielding: Dielectric Permittivity

Data Source

PatentUS11342649B2Flexible waveguides having a ceramic core surrounded by a lower dielectric constant cladding for terahertz applications

Publication Date: 2022.05.24 CORNING INC

AI summary

The THz waveguides disclosed herein are used to transmit signals having a THz frequency in the range from 0.1 THz to 10 THz and include an alumina core surrounded by an optional cladding. The core may have a diameter (D1) in the range from 10 μm to 500 μm and may be comprised of a ceramic ribbon having a dielectric constant (Dk). The optional cladding may have a dielectric constant (Dk) less than the core. The THz waveguides can be formed using a continuous firing process and nano-perforation technology that enables access to a wide form factor range. In one example, rectangular waveguides, or ribbons, may be fabricated in the 10 μm to 200 μm thick range at widths in the range from sub-millimeters to several meters and lengths in the range from millimeters to several hundred meters.