Circular Grating Resonator In-Plane Electrode Nodal Placement
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Solution Overview
Problem
Incorporating electrically conducting materials into circular grating resonators for electro-optical modulation is challenging due to light absorption, leading to high losses and increased complexity, especially when electrodes are placed out-of-plane.
Innovation Solution
The use of in-plane electrodes located at nodal planes of the electric field, minimizing absorption and suppressing unwanted resonance modes, with optional trenches to further suppress additional resonances, allows for efficient electro-optical control without degrading the resonator's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrically conducting materials are incorporated into circular grating resonators for electro-optical modulation, then electro-optical control capability is improved, but optical losses increase due to light absorption
Solution Approach 1:
The patent applies local quality by positioning electrodes specifically at nodal planes of the electric field distribution within the resonator. At these nodal planes, the electric field intensity is zero or minimal, creating localized regions where conducting materials do not absorb significant optical energy. This allows electro-optical control to be implemented while minimizing optical losses from the conducting electrode materials.
Solution Approach 2:
The patent uses the nodal plane regions as intermediaries between the optical field and the electrode structures. These nodal planes act as spatial mediators that allow the electrode to influence the resonator's optical properties through the electro-optic effect while the zero-field condition prevents direct optical absorption by the conducting material.
2Adaptability or versatility
If electrodes are placed out-of-plane to achieve electro-optical modulation, then control capability is improved, but device complexity increases
Solution Approach 1:
The patent resolves the complexity issue by transitioning from out-of-plane electrode placement to in-plane electrode configuration. Instead of positioning electrodes above or below the resonator plane (out-of-plane), the electrodes are placed within the same plane as the resonator structure, specifically at the nodal planes. This dimensional reconfiguration simplifies fabrication while maintaining electro-optical control capability.
3Loss of energy
If in-plane electrodes are used at nodal planes, then optical losses are reduced, but fabrication precision requirements increase
Solution Approach 1:
The patent applies universality by designing the electrode structure to contact the center disc at multiple nodal plane locations simultaneously. This multi-point contact approach provides fabrication tolerance, as precise positioning at a single nodal plane is not required. The electrode structure can effectively engage with the center disc at several nodal positions, making the device more robust to manufacturing variations while still achieving low optical loss.
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 configuration reduces optical losses and simplifies fabrication by minimizing electric field interference and eliminating the need for cladding, while maintaining the resonator's performance and ease of fabrication.
Implementation Method 1
The electric field changes the index of refraction of the resonator and hence its resonance frequency. In so doing, an input optical signal to the resonator may be switched on and off.
Implementation Method 2
CGRs offer full two-dimensional light confinement
Data Source
AI summary
A method of forming an optical structure includes forming a circular grating resonator (CGR) on a substrate, the CGR including a center disc and a plurality of concentric rings spaced from one another; forming an input planar waveguide and an output planar waveguide on the substrate, the input planar waveguide and the output planar waveguide optically coupled to the CGR; and forming an electrode pair on the substrate, coplanar with the input and output planar waveguides, the electrode pair comprising an electrically conductive material in contact with opposing ends of the center disc of the CGR so as to render the CGR capable of electro-optical control.