Optical Waveguide Ground Electrode Slit Design
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Solution Overview
Problem
Conventional optical waveguide elements experience a dip phenomenon in high frequency characteristics, which is not effectively addressed by existing solutions that complicate manufacturing processes and increase costs.
Innovation Solution
The optical waveguide element features a substrate with an electro-optic effect, an optical waveguide, and a control electrode with a signal electrode and a ground electrode. The ground electrode is split into a first and second ground electrode by a slit, optimizing the electric field distribution to suppress substrate mode coupling and the dip phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional ground electrode configuration is used, then the electric field is enhanced near the optical waveguide, but the high-frequency microwave couples with substrate mode causing dip phenomenon
Solution Approach 1:
The ground electrode is divided into multiple segments (first ground electrode and second ground electrode) separated by a slit. This segmentation prevents the formation of continuous substrate modes while maintaining electric field enhancement near the optical waveguide, thereby suppressing the dip phenomenon in high-frequency characteristics.
2Reliability
If a low dielectric constant portion is locally formed in the holding substrate to suppress dip phenomenon, then the frequency characteristics are improved, but the manufacturing process is complicated and manufacturing cost increases
Solution Approach 1:
Instead of modifying the holding substrate's dielectric properties, the invention changes the geometric parameters of the ground electrode by introducing a slit. This parameter change achieves dip phenomenon suppression through electric field redistribution without complicating the manufacturing process or increasing manufacturing cost.
3Power
If the substrate thickness is reduced to improve electric field efficiency, then the modulation efficiency is improved, but the mechanical strength is reduced requiring a holding substrate
Solution Approach 1:
The ground electrode segmentation through slit formation allows the use of thin substrates for improved electric field efficiency while the holding substrate provides mechanical support. The slit configuration ensures that even with reduced substrate thickness, the structural integrity is maintained and dip phenomenon is suppressed.
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 effectively suppresses the dip phenomenon in frequency characteristics while maintaining a simplified manufacturing process, thereby reducing manufacturing costs.
Implementation Method 1
a substrate (1) having an electro-optic effect
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An optical waveguide element (OE) includes a substrate (1) having an electro-optic effect, an optical waveguide (2) formed in the substrate, and a control electrode arranged on the substrate (1) to modulate a light wave propagating through the optical waveguide. The control electrode includes a signal electrode (S) and a ground electrode. The signal electrode (S) and the ground electrode are arranged along a modulation effect portion of the optical waveguide that performs modulation. In a shape of a bottom surface of the ground electrode facing the substrate, a slit (SL) separating the ground electrode into a first ground electrode (G1) close to the signal electrode (S) and a second ground electrode (G2) far from the signal electrode (S) is formed in a range corresponding to the modulation effect portion.