Semiconductor Optical Waveguide with Low-Refractive Conductive Cladding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical modulators using polycrystalline and amorphous silicon suffer from significant optical propagation losses due to light scattering, which limits the performance of semiconductor devices in silicon photonics applications.
Innovation Solution
A semiconductor device with an optical waveguide structure that includes a dielectric layer and a conductive layer with a refractive index lower than the semiconductor layer, effectively confining light and reducing scattering losses by acting as a cladding layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a second semiconductor layer made of polycrystalline silicon or amorphous silicon is formed on the insulating layer, then the optical modulator can change carrier density in the optical waveguide to adjust light phase, but optical propagation losses become large due to light scattering by the second semiconductor layer
Solution Approach 1:
The patent removes the second semiconductor layer (polycrystalline silicon or amorphous silicon) that causes light scattering, extracting the harmful element from the system. The insulating layer is left exposed on the upper surface of the optical waveguide, eliminating the source of optical propagation losses while preserving the phase modulation functionality through carrier density control in the first semiconductor layer.
Solution Approach 2:
The patent applies different material properties to different regions: the first semiconductor layer maintains semiconductor characteristics for carrier density control, while the insulating layer provides optical transparency and low scattering in the region where light propagates. This local differentiation optimizes both electrical control and optical transmission properties.
2Reliability
If light is substantially confined within the optical waveguide, then phase modulation can be achieved, but a portion of light still seeps out and is scattered by the second semiconductor layer
Solution Approach 1:
The patent converts the potential harm of light seeping out by removing the scattering source (second semiconductor layer) and allowing the insulating layer to interact with the evanescent field. The insulating layer, being optically transparent, transforms what would be a loss mechanism into a non-harmful interaction, maintaining light confinement benefits while eliminating scattering losses.
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
The proposed structure significantly reduces optical losses by preventing light from escaping and scattering, thereby enhancing the performance and characteristics of semiconductor devices with optical waveguides.
Implementation Method 1
A refractive index of a material of the conductive layer is smaller than refractive index of a material of the first semiconductor layer
Data Source
AI summary
A semiconductor device has a first semiconducting layer including an optical waveguide, a dielectric layer formed on the optical waveguide, and a conductive layer formed on the dielectric layer. A refractive index of a material of the conductive layer is smaller than a refractive index of a material of the first semiconductor layer.