Multi-Layer Ground Electrodes for Crosstalk Reduction in Waveguide Optical Elements
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Solution Overview
Problem
Nested optical modulators face challenges in reducing electric crosstalk between signal electrodes while maintaining high-frequency characteristics and avoiding manufacturing complexity, particularly in achieving downsized and wider bandwidth optical transmission systems.
Innovation Solution
The design incorporates a waveguide optical element with signal electrodes and ground electrodes structured in multiple layers, where the distance and thickness of the ground electrodes are strategically varied to confine electric fields, reducing crosstalk without increasing the complexity of the manufacturing process or altering high-frequency characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the height of the signal electrode is increased to reduce conductor loss and secure high-frequency characteristics, then the conductor loss is reduced, but the shielding effect of the ground electrode is limited and electric crosstalk between adjacent signal electrodes becomes more remarkable
Solution Approach 1:
The invention transitions from a single-layer ground electrode structure to a multi-layer ground electrode structure. Specifically, a first ground electrode layer is formed beneath the signal electrodes, and a second ground electrode layer is formed above the first layer, creating a three-dimensional shielding configuration that effectively contains electric fields and reduces crosstalk between adjacent signal electrodes.
Solution Approach 2:
The ground electrode layers are nested around the signal electrodes, with the first ground electrode layer positioned below and the second ground electrode layer positioned above, creating a nested shielding structure that confines the electric fields generated by the signal electrodes and prevents interference with adjacent signal electrodes.
2Object-generated harmful factors
If the interval between signal electrodes is widened to suppress electric crosstalk, then the crosstalk is reduced, but the size of the nested optical modulator in both width and length directions is increased
Solution Approach 1:
The ground electrode layers serve as intermediary shielding structures between adjacent signal electrodes. The first ground electrode layer beneath and the second ground electrode layer above create an electromagnetic shielding barrier that mediates the interaction between adjacent signal electrodes, effectively reducing crosstalk while allowing the electrodes to remain in close proximity and maintaining compact device dimensions.
3Productivity
If a multilevel modulation form using phase modulation is applied to increase optical transmission capacity, then the transmission capacity is increased, but the complexity of the optical modulator structure increases with multiple parallel waveguides and signal electrodes
Solution Approach 1:
The optical modulator is segmented into multiple parallel waveguide structures, each with its own signal electrode and ground electrode layers. This segmentation allows independent phase modulation of each waveguide, enabling multilevel modulation formats such as QPSK and 16QAM to achieve high transmission capacity while maintaining manageable structural complexity through modular design.
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 minimizes electric crosstalk between signal electrodes while maintaining the necessary electric field for optical waveguides, ensuring stable high-frequency performance and preventing deterioration of modulation characteristics, thus supporting increased bandwidth and capacity in optical transmission systems.
Implementation Method 1
a first ground electrode layer and a second ground electrode layer formed on the first ground electrode layer, the second ground electrode layer being formed so as to be spaced apart from an adjacent signal electrode at a second distance larger than a first distance from the adjacent signal electrode to the first ground electrode layer
Implementation Method 2
a waveguide optical element such as an optical modulator in which an optical waveguide is formed on a substrate having an electro-optic effect
Data Source
AI summary
A waveguide optical element which includes a plurality of optical waveguides provided on a substrate having an electro-optic effect includes: a plurality of signal electrodes controlling light waves propagating through the optical waveguides; and a plurality of ground electrodes provided so as to interpose each of the signal electrodes therebetween, in which at least one of the ground electrodes includes a first layer and a second layer formed on the first layer, the second layer is formed such that a distance between the second layer and the signal electrode adjacent to the second layer is larger than a distance between the first layer and said signal electrode adjacent to said second layer, and a thickness of the ground electrode which includes the first layer and the second layer is 25 μm or more.