Optical Modulator Reflection Layer Using Dielectric DBR
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Solution Overview
Problem
Current optical modulators with reflection layers require a large number of stacked layers, leading to increased thickness and manufacturing complexity, which hinders their efficiency and cost-effectiveness in applications such as 3D imaging and distance measurement.
Innovation Solution
The optical modulator design incorporates a dielectric material-based upper reflection layer with a distributed Bragg reflection (DBR) structure, reducing the total thickness and layer count by using a stack of dielectric material layers with different refractive indices, along with micro cavity layers, to achieve constructive interference within specific wavelength ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional group III-V compound semiconductor-based reflection layers are used, then effective transmittance modulation is achieved, but the number of stacked layers increases and thickness increases
Solution Approach 1:
The patent changes the material composition parameter of the reflection layer from traditional group III-V compound semiconductors to a combination of dielectric materials (TiO2, SiO2, Al2O3) and metal materials (Ag, Au, Al). This material substitution reduces the number of stacked layers from multiple semiconductor layers to a more compact multilayer structure while maintaining the necessary optical path difference for effective transmittance modulation in the infrared range.
Solution Approach 2:
The patent employs composite materials by combining dielectric materials with different refractive indices (TiO2 with high refractive index, SiO2 and Al2O3 with lower refractive indices) along with metal materials (Ag, Au, Al). This composite approach creates a distributed Bragg reflector structure that achieves the required optical interference effects with fewer layers compared to traditional single-material semiconductor-based reflection layers.
2Reliability
If traditional group III-V compound semiconductor-based reflection layers are used, then effective transmittance modulation is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent simplifies manufacturing by changing the material parameters to dielectric and metal materials that can be deposited using standard thin-film deposition techniques such as sputtering, evaporation, or chemical vapor deposition. These materials and methods are more成熟 and easier to manufacture than precise control of multiple group III-V compound semiconductor layers, reducing fabrication complexity while maintaining optical performance.
Solution Approach 2:
The patent applies local quality by assigning specific materials to specific functional requirements: dielectric materials (TiO2, SiO2, Al2O3) are positioned to create optical interference and reflection, while metal materials (Ag, Au, Al) are used to enhance reflectivity and electrical conductivity. This localized material optimization simplifies the overall manufacturing process compared to uniform use of complex semiconductor materials throughout the structure.
3Reliability
If more stacked layers are used in the reflection layer, then optical performance is improved, but thickness increases
Solution Approach 1:
The patent changes the optical parameters by using materials with high refractive index contrast (TiO2, SiO2, Al2O3, Ag, Au, Al) to achieve the required optical path difference in a shorter physical distance. The high refractive index materials allow for quarter-wave thicknesses that are physically thinner while still providing the necessary optical phase shifts for effective distributed Bragg reflection and transmittance modulation.
Solution Approach 2:
The composite multilayer structure using dielectric and metal materials creates stronger optical interference effects per unit thickness compared to traditional semiconductor layers. The combination of high-refractive-index dielectrics and highly reflective metals achieves the required reflectivity and modulation depth with fewer and thinner layers, reducing the overall reflection layer thickness while maintaining or improving optical performance.
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 design reduces the thickness and manufacturing complexity of the upper reflection layer, enhancing the modulator's efficiency and cost-effectiveness while maintaining effective transmittance modulation, as demonstrated by the reduced transmittance difference bandwidth and overall layer thickness compared to traditional group III-V compound semiconductor-based modulators.
Implementation Method 1
a DBR layer comprising a plurality of layers having optical thicknesses configured to cause constructive interference with respect to light having a wavelength within a range of 780 nm to 1650 nm
Implementation Method 2
At least one of the plurality of micro cavity layers may have an optical thickness of λ/2, where λ is a resonant wavelength of the optical modulator
Implementation Method 3
The upper reflection layer may include at least one pair of a first dielectric material layer having a first refractive index and a second dielectric material layer having a second refractive index that is different from the first refractive index
Data Source
AI summary
An optical modulator is provided, including a lower reflection layer, an active layer formed on the lower reflection layer, and an upper reflection layer formed on the active layer. The active layer includes a multiple quantum well structure including a quantum well layer and a quantum barrier layer. The upper reflection layer includes a dielectric material. A plurality of micro cavity layers are included in the upper reflection layer.