Semiconductor Photonic Modulator With Lateral p-i-n and Buried Coupling
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Solution Overview
Problem
Conventional electro-absorption modulators (EAMs) with a vertical structure have large junction capacitance and narrow CR band, making high-speed operation and low power consumption difficult due to the confined waveguide structure.
Innovation Solution
A semiconductor photonic device with a lateral p-i-n structure, featuring a buried optical coupling layer that reduces light absorption and waveguide loss, allowing for smaller junction capacitance and higher CR band operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a vertical p-i-n structure with mesa width of 1 to 2 μm is used to strongly confine guided light in the active layer, then light confinement is improved, but junction capacitance becomes very large and CR band becomes narrow
Solution Approach 1:
The patent transitions from a vertical p-i-n structure to a lateral p-i-n structure, changing the dimension of current flow and light modulation. In the lateral structure, the current flows horizontally through the active layer rather than vertically, allowing for smaller junction capacitance while maintaining effective light confinement through the optical coupling layer positioned beneath the active layer.
2Illumination intensity
If a vertical p-i-n structure with mesa width of 1 to 2 μm is used to strongly confine guided light in the active layer, then light confinement is improved, but power consumption increases and costs cannot be lowered
Solution Approach 1:
The lateral p-i-n structure enables more efficient electrical and optical coupling compared to the vertical structure. The horizontal current path and positioned optical coupling layer reduce the voltage required for modulation, thereby lowering power consumption while achieving effective light modulation.
3Ease of operation
If the optical coupling layer is formed with a material that absorbs more light, then coupling efficiency may be improved, but waveguide loss increases
Solution Approach 1:
The patent applies local quality by positioning the optical coupling layer specifically beneath the active layer region where optical coupling is needed, rather than throughout the entire waveguide structure. This localized approach enables effective coupling while minimizing overall waveguide loss, as the coupling layer material properties are optimized only in the necessary region.
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 device achieves lower power consumption and reduced costs by optimizing the optical coupling layer's design, enabling high-speed operation and efficient light modulation with reduced waveguide loss.
Implementation Method 1
an optical coupling layer that is buried in the first cladding layer so as to be optically coupled to the active layer
Implementation Method 2
applies an electric field in a direction perpendicular to the active layer with the above-described vertical p-i-n structure, to modulate light intensity with a quantum confined Stark effect (QCSE)
Data Source
AI summary
A semiconductor photonic device includes a first cladding layer formed on a substrate formed with Si, a semiconductor layer formed on the first cladding layer, and a second cladding layer formed on the semiconductor layer. In the semiconductor layer, an active layer, and a p-type layer and an n-type layer disposed in contact with the active layer while sandwiching the active layer in a planar view are formed. A p-type electrode is electrically connected to the p-type layer, and an n-type electrode is electrically connected to the n-type layer. The active layer is formed in a core shape extending in a predetermined direction. This semiconductor photonic device also includes an optical coupling layer that is buried in the first cladding layer in such a manner as to be optically coupled to the active layer, and is formed in a core shape extending along the active layer.