Optical Waveguide Protrusion Design for Sticking Prevention
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Solution Overview
Problem
Existing optical waveguide sensors face challenges in achieving high sensitivity and reliability due to mechanical strength issues and low reliability caused by floating waveguide structures, which lead to sticking problems and reduced interaction with evanescent waves.
Innovation Solution
An optical waveguide with a substrate, core layer, and intermittently arranged supports and protrusions that deviate from the central position, reducing sticking and enhancing interaction with evanescent waves by minimizing optical absorption and maintaining mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a portion of the waveguide is floated with respect to the substrate using intermittently arranged support structures, then the region of interaction between the substance to be measured and the evanescent wave is increased, but the mechanical strength of the sensor deteriorates and reliability decreases
Solution Approach 1:
The support structures are divided into intermittently arranged discrete supports rather than continuous support, creating spaced segments that allow evanescent wave interaction while maintaining mechanical stability through strategic positioning
Solution Approach 2:
Protrusions are added in the vertical dimension from the substrate to hold the core layer at a specific height, creating a three-dimensional structure that separates the core layer from the substrate in the vertical direction while maintaining horizontal connectivity through supports
2Measurement precision
If the core layer is floated with respect to the substrate, then the region of interaction with evanescent wave is increased, but sticking between the core layer and substrate occurs reducing reliability
Solution Approach 1:
The space between substrate and core layer is segmented into regions with supports and regions without supports, with protrusions strategically placed to prevent sticking only where necessary while maintaining interaction regions elsewhere
Solution Approach 2:
Protrusions act as intermediary structures that physically separate the core layer from the substrate at critical points, preventing direct contact and sticking while allowing the core layer to remain generally close to the substrate for evanescent wave interaction
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 improves sensitivity and reliability by reducing sticking and optical absorption, allowing for stable and accurate measurement of gas or liquid concentrations.
Implementation Method 1
When a refractive index of a material of a structure, such as a thin film formed from crystals or the like, is greater than a refractive index of a material external to the structure, light transmitted through the structure travels repeatedly undergoing total internal reflection at the boundary between the structure and the outside of the structure.
Implementation Method 2
Such an extension is referred to as an evanescent wave, which can be absorbed by a substance adjacent to the structure 51 when the light L is transmitted through the structure 51.
Implementation Method 3
protrusions that are intermittently arranged in the longitudinal direction in a space between the substrate and the core layer and protrude toward the core layer from the substrate
Data Source
AI summary
Sticking of core layer is suppressed, and deterioration of sensitivity of a sensor is prevented. An optical waveguide (10) includes a substrate (15), a core layer (11), a support, and a protrusion (18). The core layer (11) can transmit light. The support connects at least a portion of the substrate (15) and a portion of the core layer (11) together. The support supports the core layer (11). The protrusion (18) is arranged at a position different from a position of the support in a space between the substrate (15) and the core layer (11). The protrusion (18) has a maximum height at a position deviated from a central position cp of the core layer (11) in a width direction. The protrusion (18) protrudes toward the core layer (11) from the substrate (15).