Non-Linear Microstructure Array for Waveguide Wavelength Filtering
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Solution Overview
Problem
Existing waveguide structures face challenges in selectively filtering specific wavelength bands due to difficulties in implementing co-dopants and limited methods for enhancing outcoupling strength, particularly in maintaining stability and avoiding excessive outcoupling at operating wavelengths.
Innovation Solution
A specific geometry is employed where elements are arranged non-radially around the waveguide core, with the first element positioned closer to the core than in traditional radial configurations, enhancing coupling strength and filtering effectiveness by optimizing the distance between elements and utilizing asymmetry to improve filtering performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If co-dopants are added to the waveguide core for wavelength selective filtering, then filtering capability is improved, but material stability deteriorates and fabrication complexity increases
Solution Approach 1:
The invention extracts the filtering function from the waveguide core by placing a separate filtering structure adjacent to the core. This eliminates the need to add co-dopants to the core material, thereby maintaining material stability while achieving wavelength selective filtering. The filtering structure is a distinct component rather than a modification of the core composition.
Solution Approach 2:
The invention introduces an intermediary filtering structure that mediates between the light source and the waveguide core. This intermediary component performs the wavelength selective filtering function without directly modifying the core material, thus avoiding the stability issues associated with co-doping while still achieving the desired filtering capability.
2Strength
If traditional radial array configuration is used, then structural symmetry is maintained, but outcoupling strength in filtering band is insufficient
Solution Approach 1:
The invention deliberately breaks the radial symmetry by positioning the filtering structure asymmetrically adjacent to the waveguide core rather than arranging elements in a symmetric radial pattern. This asymmetry creates stronger evanescent field coupling between the core mode and the filtering structure modes, thereby enhancing outcoupling strength in the filtering band while sacrificing perfect structural symmetry.
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 design significantly enhances outcoupling in the filtering band by 5-10 dB, reduces offset between the core and filtering elements by 13%, and allows for additional parity modes, effectively filtering wavelengths between 900 and 1100 nm while maintaining low loss outside the band.
Implementation Method 1
enhances the strength of the outcoupling from the core in a selected filtering band
Data Source
AI summary
A non-radial array of microstructure elements provides enhanced wavelength selective filtering. The elements are arranged along a line that does not intersect the center of the core. In this configuration, the first coupling element in an array that is nearest to the core is a non-integer array unit spacing from the main waveguide where the array unit spacing is defined as the flat to flat distance of a hexagonal cell.