Non-Rectangular Optical Waveguides for Slit Illumination Homogenization
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Solution Overview
Problem
Existing spectro-imaging instruments face challenges in achieving scene-independent spectral response due to non-uniform illumination, particularly in the across-track direction, leading to errors in gas concentration estimation, especially with high spectral resolution requirements.
Innovation Solution
Employing optical waveguides with non-rectangular cross-sections, such as pentagons or trapezoids, to homogenize the optical slit, ensuring uniform illumination distribution regardless of scene geometry, thereby improving homogenization performance without the need for long fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional rectangular optical waveguides are used in the optical slit, then the structure is simple and manufacturing is easy, but the homogenization performance is insufficient and spectral response remains dependent on scene geometry
Solution Approach 1:
The patent applies asymmetry by replacing the traditional symmetric rectangular waveguide cross-section with asymmetric shapes (trapezoidal, pentagonal, or triangular). This asymmetric geometry creates more complex internal reflection paths that effectively homogenize the optical field, making the spectral response independent of scene geometry while maintaining manufacturability through standard fabrication processes.
Solution Approach 2:
The patent changes the geometric parameters of the waveguide cross-section from a simple rectangle to shapes with varying side lengths and angles (trapezoidal with specific height-to-base ratios, pentagonal with defined internal angles). These parameter changes optimize the internal light propagation paths to achieve superior homogenization performance.
2Measurement precision
If long optical fibers are used to achieve homogenization, then the homogenization performance improves, but the device compactness deteriorates and the instrument becomes more complex
Solution Approach 1:
The patent changes the geometric parameters of the waveguide cross-section to optimize internal reflection paths, achieving effective homogenization in shorter waveguide lengths. The specific trapezoidal, pentagonal, or triangular shapes with defined dimensions create more efficient light mixing paths compared to traditional rectangular waveguides, reducing the required length while maintaining or improving homogenization performance.
Solution Approach 2:
The patent employs curved or angled faces in the waveguide cross-section (trapezoidal with inclined sides, pentagonal with varied angles) to create more complex and efficient internal reflection paths. This geometric curvature and angulation enhance light mixing and homogenization within a compact volume, eliminating the need for long fiber lengths.
3Use of energy by moving object
If the optical slit is designed to collect maximum energy, then the energy collection efficiency is high, but the illumination uniformity across the slit decreases
Solution Approach 1:
The asymmetric waveguide cross-sections (trapezoidal, pentagonal, triangular) are designed to balance energy collection and uniformity distribution. The specific geometric configurations optimize the trade-off by creating internal reflection paths that distribute light more evenly while maintaining high overall transmission efficiency, unlike symmetric rectangular waveguides that favor one aspect over the other.
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 superior homogenization, maintaining high energy collection and compactness, while ensuring the spectral response is independent of scene non-uniformities, thus enhancing gas concentration estimation accuracy.
Implementation Method 1
optical waveguides with non-rectangular cross-sections, such as pentagons or trapezoids, to homogenize the optical slit
Implementation Method 2
Employing optical waveguides with non-rectangular cross-sections, such as pentagons or trapezoids, to homogenize the optical slit
Data Source
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AI summary
Optical component for an observation or measurement instrument in a spectral range, said optical component comprising a plurality of optical waveguides (8) of all constant sections between each an input and an output of the waveguide, with multimode behavior in said spectral range, and whose input ends are aligned along an axis (5) which is a median longitudinal axis of an optical slit (1) of said optical component, said sections each having two bases (B) opposite one another, substantially rectilinear and parallel to the axis (5) of the slit. Each of the sections has, to connect said two bases, at least one inclined face (6) or a curved face (7), distinguishing said section from a rectangle.