Optical Waveguide Scattering Portions for Spectrometer
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Solution Overview
Problem
Optical Bragg gratings suffer from undesired dispersive scattering, leading to light attenuation, particularly in Type II gratings written by high intensity UV or femtosecond lasers, which limits their application in optical systems due to strong losses and complexity.
Innovation Solution
An optical waveguide with a first refractive index interrupted by portions of a second refractive index, where each portion has a long axis perpendicular and a short axis perpendicular to the light propagation axis, allowing for controlled scattering and interference effects to efficiently couple and detect light, potentially eliminating the need for additional optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Optical Bragg gratings are used to reflect or couple out light, then wavelength-specific optical filtering is achieved, but dispersive scattering causes strong light attenuation and loss
Solution Approach 1:
The grating is segmented into multiple sections along the light propagation direction, with each section having different orientation angles. This segmentation allows control over scattering directions, directing useful reflected light while separating harmful scattered light, thus reducing overall light attenuation while maintaining wavelength selection precision
Solution Approach 2:
Different sections of the grating are assigned different local properties (orientation angles) to achieve different functions. The first section reflects light in a first direction while the second section reflects light in a second direction, allowing spatial separation of scattered light from useful reflected light, thereby reducing attenuation in the useful path
2Measurement precision
If tilted fiber Bragg gratings are used to couple out light, then wavelength and polarization selectivity is achieved, but the grating occupies a long segment of the fiber and increases device complexity
Solution Approach 1:
The grating is divided into multiple sections with different orientation angles along the light propagation direction. This segmentation enables compact design by achieving wavelength and polarization selectivity through spatially distributed sections rather than requiring a single long tilted grating, thus reducing overall device complexity
Solution Approach 2:
The invention introduces angular orientation as an additional dimension for controlling light interaction. By varying the orientation angle of different grating sections, the system achieves wavelength and polarization selectivity without requiring excessive length along the fiber, effectively utilizing the angular dimension to reduce spatial requirements
3Ease of manufacture
If high intensity UV or femtosecond lasers are used to write Type II gratings, then grating formation is achieved, but pulse energy above damage threshold causes strong diffractive scattering losses
Solution Approach 1:
The grating is segmented into multiple sections, each written with controlled laser parameters. This allows the use of high intensity lasers for efficient grating formation while limiting the interaction length in each section, thereby reducing cumulative diffractive scattering losses compared to a single long grating written with the same parameters
Solution Approach 2:
The invention uses partial action by creating multiple discrete grating sections rather than a continuous long grating. Each section is written with sufficient laser energy to achieve the desired grating strength, but the total length is limited, thus achieving manufacturing effectiveness while controlling scattering losses through partial rather than excessive grating length
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
This approach enables efficient coupling and detection of light at specific angles, simplifying optical apparatuses like spectrometers by leveraging scattering effects for wavelength discrimination and focusing, resulting in smaller, more cost-effective devices with improved spectral resolution.
Implementation Method 1
an optical waveguide configured to guide light along a light propagation axis
Implementation Method 2
receive light scattered from the plurality of portions in a scattering direction lying in a main scattering plane
Implementation Method 3
The Bragg grating is constituted by a periodic variation in the refractive index of the fiber core generating a wavelength-specific dielectric mirror due to selected interferences
Data Source
AI summary
The present invention relates to an apparatus for optical applications, a spectrometer system and method for producing an apparatus for optical applications, and in particular to an apparatus comprising an optical waveguide having a first refractive index along a light propagation axis interrupted by a plurality of scattering portions having a second refractive index. Each scattering portion has a long axis substantially perpendicular to the light propagation axis as well as a short axis substantially perpendicular to the light propagation axis and the long axis. A receiver unit or a transmitter unit is arranged on a side of the optical waveguide, the long axis being substantially perpendicular, i.e. normal to the plane of this side on which the receiver unit or transmitter unit is arranged. Accordingly, simplification and miniaturization of an optical apparatus can be realized.