Optical Waveguide Device Impedance Matching Buffer Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical waveguide devices face challenges in achieving impedance matching and velocity matching between light waves and modulation signals, particularly when using support substrates with low dielectric constants, which also complicates manufacturing and increases propagation loss.
Innovation Solution
The optical waveguide device includes a substrate with an optical waveguide of a rib type and modulation electrodes that interpose the optical waveguide. The modulation electrodes feature segment electrodes and a signal transmission portion with different thicknesses, where a buffer layer is placed between the signal transmission portion and the optical waveguide but not between the substrate and the segment electrode, facilitating impedance and velocity matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a support substrate with a low dielectric constant is used to widen bandwidth, then bandwidth is improved, but impedance matching and velocity matching become difficult to achieve
Solution Approach 1:
The patent changes the physical parameters of the electrode structure by introducing a buffer layer with specific dielectric constant between the electrode and the low dielectric constant substrate. This parameter change compensates for the impedance mismatch caused by the low dielectric constant substrate, enabling both wide bandwidth and proper impedance matching to be achieved simultaneously.
Solution Approach 2:
The buffer layer acts as an intermediary between the electrode and the low dielectric constant substrate. It mediates the electromagnetic field interaction, providing a transition zone that enables impedance matching while allowing the electrode to function properly on the low dielectric constant substrate for bandwidth enhancement.
2Manufacturing precision
If segment electrodes are used to increase adjustable parameters, then impedance matching capability is improved, but electrode thickness cannot be increased which limits bandwidth widening
Solution Approach 1:
The electrode is divided into multiple segment electrodes with different positions and orientations. This segmentation provides multiple adjustable parameters for impedance matching while the buffer layer enables the electrode to be made thicker for bandwidth enhancement without compromising the segment electrode structure.
Solution Approach 2:
The patent uses a composite structure combining segment electrodes with a buffer layer material. This composite approach allows the electrode to have both the segmentation needed for impedance matching and the thickness needed for bandwidth, by combining the electrical functionality of the electrode with the dielectric properties of the buffer layer.
3Adaptability or versatility
If T-shape segment electrodes are used, then electrode configuration flexibility is improved, but aspect ratio increases making manufacturing more difficult
Solution Approach 1:
The buffer layer serves as an intermediary that decouples the manufacturing complexity from the electrode configuration flexibility. It allows T-shape and other complex electrode configurations to be implemented without directly transferring their manufacturing difficulties to the electrode fabrication process, as the buffer layer provides a uniform base layer.
4Use of energy by moving object
If electrodes are formed directly on the substrate to reduce drive voltage, then drive voltage is reduced, but light wave absorption and scattering increase propagation loss
Solution Approach 1:
The buffer layer acts as an intermediary between the electrode and the optical waveguide, preventing direct contact that would cause light absorption and scattering. It maintains the electric field coupling needed for low drive voltage while physically separating the electrode from the optical path to reduce propagation loss.
Solution Approach 2:
The buffer layer is strategically placed only where needed - between the electrode and the optical waveguide in the regions where electric field interaction is required. This local application maintains the beneficial electric field coupling for low drive voltage while minimizing the impact on optical propagation.
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 allows for easy manufacturing and effective impedance and velocity matching, reducing propagation loss and enabling the production of compact, high-performance optical modulation devices and transmission apparatuses.
Implementation Method 1
the electrodes are disposed in contact with the optical waveguide 10 and cross the optical waveguide, and thus the light wave propagating through the optical waveguide is absorbed or scattered, resulting in an increase in a propagation loss of the signal
Implementation Method 2
modulation electrodes disposed on the substrate to interpose the optical waveguide of the rib type
Data Source
Figure 1A~1D
Figure 2A~2D
Figure 3A~3B
AI summary
An optical waveguide device includes a substrate, an optical waveguide of a rib type formed on the substrate, and modulation electrodes disposed on the substrate to interpose the optical waveguide of the rib type, in which the modulation electrodes include a plurality of segment electrodes disposed in proximity to the optical waveguide of the rib type and disposed along the optical waveguide of the rib type, and a signal transmission portion electrically connected to the segment electrode and transmitting a modulation signal, a thickness of the signal transmission portion is larger than a thickness of the segment electrode, a buffer layer is disposed between the signal transmission portion and the optical waveguide of the rib type in at least a portion where the signal transmission portion crosses the optical waveguide of the rib type, and no buffer layer is disposed between the substrate and the segment electrode.