Multi-Layer Silicon Light Control Element for High-Efficiency Modulation
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Solution Overview
Problem
The silicon optical modulator has low modulation efficiency due to limited overlap between refractive index modulation regions and electric field distribution, leading to increased element size, high drive voltage requirements, and high power consumption.
Innovation Solution
A light control element with three or more silicon thin-film layers and dielectric layers, where the silicon thin-film layers are arranged to partially overlap and have different conductivity types, allowing for efficient light confinement and refractive index modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicon optical modulator uses a conventional two-layer structure with limited overlap between refractive index modulation regions and electric field distribution, then the structure is simple, but the modulation efficiency is low
Solution Approach 1:
The optical waveguide is divided into multiple silicon thin-film layers (first, second, and third silicon thin-film layers) with different conductivity types arranged in sequence. This segmentation allows the refractive index modulation regions to be distributed across multiple layers, increasing the overlap with the electric field distribution and thereby improving modulation efficiency while maintaining a manageable structural complexity through systematic layering.
2Area of moving object
If the element size is reduced to improve integration, then integration capability improves, but the drive voltage increases
Solution Approach 1:
Different silicon thin-film layers are doped with different conductivity types (n-type and p-type) to create localized regions with optimized electrical properties. This local quality differentiation allows for reduced element size while maintaining effective carrier modulation, as each layer contributes differently to the overall modulation effect, thereby reducing the drive voltage required compared to a uniformly structured small element.
3Reliability
If the overlap between refractive index modulation regions and electric field distribution is increased to improve modulation efficiency, then modulation efficiency improves, but the element size increases
Solution Approach 1:
The patent transitions from a planar two-layer structure to a three-dimensional multi-layer structure with silicon thin-film layers stacked in the vertical dimension. This dimensional change allows the refractive index modulation regions to overlap with the electric field distribution in multiple layers simultaneously, achieving high modulation efficiency without requiring a large horizontal element size, thus compacting the overall device volume.
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 reduces the size and drive voltage of the light control element, enabling high-speed operation with lower power consumption and eliminating the need for additional driver circuits.
Implementation Method 1
The silicon optical waveguide has a stronger action to confine light inside the waveguide than the lithium niobate optical waveguide
Implementation Method 2
The variation in the carrier density changes a refractive index by the carrier plasma effect, thereby modulating the phase of the light propagating through the region 101
Data Source
AI summary
A light control element includes three or more silicon thin-film layers (522, 524, 526) placed on a first dielectric layer (521), second dielectric layers (523, 525) placed between the three or more silicon thin-film layers (522, 524, 526), and a third dielectric layer (529) placed to surround the silicon thin-film layers and the second dielectric layers. The three or more silicon thin-film layers are arranged to partially overlap with one anther. In the part where the silicon thin-film layers overlap, the second dielectric layers are placed between the silicon thin-film layers. In the three or more silicon thin-film layers, the silicon thin-film layers adjacent to each other have different conductivity types.