Optical Modulator Electrode Configuration for High Density
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Solution Overview
Problem
Conventional optical modulators require high voltages and large electrode spacings, making it difficult to achieve high-density channel arrangements and efficient high-speed modulation, while also being prone to discharge issues.
Innovation Solution
An optical modulator with a periodically-poled structure, where alternating polarization parts are arranged in a specific pattern, allowing for reduced voltage application and high-density electrode arrangements by individually controlling voltages between electrodes, preventing discharge and enabling efficient light modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the distance between electrode elements is shortened to achieve high-density channel arrangement, then the channel density is improved, but discharge (leakage) between electrode elements occurs
Solution Approach 1:
The patent transitions from a planar electrode arrangement to a three-dimensional configuration by placing first electrodes on the upper surface and second electrodes on the lower surface of the substrate. This spatial separation in the thickness direction allows shorter lateral distances between electrode groups while maintaining sufficient physical separation to prevent discharge, thereby achieving high-density channel arrangement without compromising reliability.
Solution Approach 2:
The electrode system is segmented into two distinct groups: first electrodes on the upper surface and second electrodes on the lower surface. Each group is independently controllable, allowing for optimized voltage application and reduced discharge risk. This segmentation enables high-density arrangement by distributing electrodes across different spatial zones rather than concentrating them in a single plane.
2Speed
If the voltage applied between electrode elements is reduced for high-speed modulation, then the modulation speed is improved, but the phase difference required for light diffraction cannot be produced
Solution Approach 1:
By utilizing the thickness direction of the substrate as an additional spatial dimension, the patent enables independent voltage control between upper and lower surface electrodes. This three-dimensional electrode configuration allows for reduced voltage operation while maintaining the necessary phase difference for light diffraction, as the electric field distribution can be optimized across the substrate thickness rather than relying solely on lateral electrode spacing.
Solution Approach 2:
The patent changes the operational parameters by applying voltages to electrode groups rather than individual adjacent electrodes. This parameter change allows for reduced voltage levels (compared to conventional high-voltage operation) while still producing the required phase difference for diffraction, enabling high-speed modulation without sacrificing diffraction efficiency.
3Manufacturing precision
If a relatively large voltage is applied between electrode elements to produce the required phase difference, then the light diffraction is achieved, but the voltage cannot be reduced for high-speed modulation
Solution Approach 1:
The patent resolves this contradiction by utilizing the thickness direction of the substrate to create a three-dimensional electrode configuration. First electrodes are placed on the upper surface and second electrodes on the lower surface, allowing the electric field to be distributed across the substrate thickness. This enables reduced voltage operation while maintaining sufficient phase difference for light diffraction, thereby achieving both high-speed modulation and proper diffraction.
Solution Approach 2:
The patent changes the voltage application parameters from high-voltage individual electrode control to lower-voltage group electrode control. By applying voltages to electrode groups on opposite surfaces rather than to adjacent electrodes in a single plane, the system achieves the required phase difference at reduced voltage levels, enabling high-speed modulation without compromising diffraction performance.
4Reliability
If the electrode elements are arrayed with large spacing to prevent discharge, then the discharge prevention is improved, but the channel density cannot be increased
Solution Approach 1:
The patent increases channel density by utilizing the thickness direction of the substrate as an additional spatial dimension. First electrodes are arranged on the upper surface and second electrodes on the lower surface, allowing lateral electrode spacing to be reduced without increasing discharge risk. The vertical separation between upper and lower surfaces provides inherent discharge protection while enabling closer lateral spacing for higher channel density.
Solution Approach 2:
The electrode system is segmented into two spatially separated groups on opposite surfaces of the substrate. This segmentation allows each electrode group to be independently controlled and positioned, enabling reduced lateral spacing between electrode groups while maintaining sufficient separation to prevent discharge. The segmented configuration thus achieves high channel density without compromising discharge prevention.
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 solution reduces the voltage required for optical modulation, enables high-density channel arrangements, and prevents discharge between electrodes, enhancing the modulator's performance and ability to handle high-definition imaging.
Implementation Method 1
a base part which is a plate-like member formed of a material of which the refractive index is changed by an electric field
Implementation Method 2
light which enters the electro-optic substrate from one end surface thereof and travels thereinside is caused to enter the electro-optic substrate at a small angle (at a large incident angle) with respect to a main surface on which the electrode elements are formed and to be totally reflected on the main surface, to thereby produce a phase difference required to diffract the light
Data Source
AI summary
In an optical modulator, a first electrode portion having a plurality of first electrodes is provided on the upper surface of a base part having a periodically-poled structure and a second electrode portion is provided on the lower surface thereof, and voltage is applied in one direction between the first electrode portion and the second electrode portion, to thereby cause a periodic change of the refractive index in a polarization-part array direction in the periodically-poled structure and diffract light which enters the base part. This allows reduction in the voltage applied between the first electrode portion and the second electrode portion, and it is thereby possible to form a desired electric field inside the periodically-poled structure while achieving a high-density channel arrangement. By reducing the voltage, the rate of the optical modulation performed by the optical modulator can be increased.