Asymmetric Electrode Arrangement in Digital Optical Modulators
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Solution Overview
Problem
Existing digital phase modulators for fiber optic signal transmission and measuring devices face limitations in increasing resolution beyond 12 or 13 bits without increasing the total chip length, due to challenges in determining the length of the smallest electrode and its impact on other electrodes.
Innovation Solution
A digital integrated optical modulator with two waveguide arms and electrodes of varying lengths arranged asymmetrically, allowing for a 16-bit configuration by subdividing electrodes into binary and non-binary groups and optimizing their placement to maintain chip length, including the longest electrode being split across both arms and the smallest electrode being as short as 1 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resolution is increased to 16 bits by using binary and non-binary electrodes, then the quantization error and noise are reduced, but the total chip length cannot be maintained due to the minimum length requirements of the smallest electrode
Solution Approach 1:
The modulator is divided into two separate waveguide arms, each carrying a portion of the electrode arrangement. This segmentation allows the electrodes to be distributed across both arms, enabling the smallest electrode to meet its minimum length requirement while the overall modulator footprint remains compact. The two arms work together to achieve the complete 16-bit resolution function.
Solution Approach 2:
Instead of arranging all electrodes sequentially in a single linear direction, the electrode arrangement extends into a second spatial dimension by utilizing two separate waveguide arms. This dimensional transition allows for more efficient packing and arrangement of electrodes, particularly enabling the smallest electrode to achieve its required minimum length without proportionally increasing the total chip area.
2Manufacturing precision
If the smallest electrode length is increased to precisely determine bit weight, then the manufacturing precision is improved, but the total chip length increases
Solution Approach 1:
By dividing the electrode system across two waveguide arms, the minimum length requirement for the smallest electrode can be satisfied without forcing a proportional increase in the total chip length. The segmentation distributes the spatial requirements more efficiently across the available structure.
Solution Approach 2:
The transition to a two-armed waveguide configuration provides an additional spatial dimension for electrode arrangement, allowing the smallest electrode to achieve its required minimum length for precise bit weight determination without extending the chip length in the primary direction.
3Reliability
If the same pulse response is obtained in both light directions by rotating electrodes 180 degrees, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The two waveguide arms are configured with different electrode arrangements relative to each other, with one arm's electrodes rotated 180 degrees compared to the other. This asymmetric configuration ensures that both arms produce identical pulse responses despite their different orientations, improving reliability while managing complexity through systematic asymmetry rather than arbitrary 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
Enables a 16-bit digital electrode arrangement while maintaining total chip length, reducing quantization error and noise, and allowing for higher bit resolutions or equal resolutions with reduced modulator length, improving optical transmission and phase shift precision.
Implementation Method 1
digital integrated optical modulator with two waveguide arms and electrodes that are arranged along both waveguide arms in or on an optical substrate
Data Source
AI summary
A digital integrated optical modulator, in particular for a fiber optical signal transmission or measuring device, having two waveguide arms and electrodes that are arranged along both waveguide arms in or on an optical substrate, wherein the arrangements of the electrodes along the two waveguide arms are different from each other.