Curved Optical Waveguide Asymmetric Electrode Gap Design
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Solution Overview
Problem
Optical waveguide devices face increased propagation loss due to optical absorption by electrodes, particularly in curved parts, which also complicates the reduction of electrode gap size and the attainment of velocity matching.
Innovation Solution
The optical waveguide is positioned with its center line outside the geometrical center line of the curved part, reducing optical absorption loss and allowing for a smaller electrode gap while minimizing propagation loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electrode gap is narrowed to reduce driving voltage, then the driving voltage is reduced, but optical absorption loss in the electrodes increases
Solution Approach 1:
The patent applies asymmetry by positioning the optical waveguide off-center within the electrode gap. Specifically, the distance from the waveguide to one electrode is made different from the distance to the other electrode, creating an asymmetric field distribution that reduces optical absorption while maintaining effective voltage application for modulation.
Solution Approach 2:
The patent implements local quality by creating a non-uniform spatial distribution of the optical waveguide within the electrode gap. The waveguide is positioned at a specific location where the electric field intensity and optical absorption characteristics are optimized locally, rather than being centered or uniformly distributed.
2Speed
If the optical waveguide is thinned to attain velocity matching, then velocity and impedance matching are achieved, but propagation loss of light increases
Solution Approach 1:
The patent introduces an intermediary buffer layer between the optical waveguide and the electrodes. This buffer layer acts as a mediator that provides electrical isolation while maintaining optical transparency, thereby reducing optical absorption loss without compromising velocity matching achieved through waveguide thinning.
Solution Approach 2:
The patent extracts the buffer layer as a separate functional component between the waveguide and electrodes. This extraction allows the buffer layer to independently perform the function of electrical isolation and optical protection, preventing direct optical absorption by the electrodes while maintaining the thin waveguide structure for velocity matching.
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 significantly reduces optical propagation loss and enables a smaller electrode gap, improving the efficiency and stability of optical waveguide devices by minimizing light absorption into the electrodes.
Implementation Method 1
an optical waveguide having a curved part, wherein a center line of the gap is provided outside of a center line of the optical waveguide with respect to a center of curvature of the curved part
Implementation Method 2
an optical waveguide device having a channel-type optical waveguide, in which the optical absorption loss by an electrode in a curved part of the optical waveguide can be reduced
Data Source
AI summary
An optical waveguide device includes a substrate of a ferroelectric material, at least a pair of electrodes 4A, 4B provided on one main face of the substrate, and a channel-type optical waveguide 5A formed in a gap 1 of the pair of the electrodes. The optical waveguide 5A has a curved part 15. A central line C of the gap 1 is provided outside of a center line WC of the optical waveguide with respect to the center O of curvature of the curved part 15.