Tapered Waveguide Structure for Photodetector Light Collection
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Solution Overview
Problem
The operation speed of photodetectors limits the detection aperture, reducing the amount of input light captured and impacting responsivity, which restricts their performance.
Innovation Solution
A waveguide structure is introduced with a first surface and a second surface of different widths, connected by a sidewall surface, enhancing light collection efficiency by confining and directing incoming optical signals towards a photosensitive region in optoelectronic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the operation speed of photodetectors is increased, then the detection aperture is reduced, but the total amount of light captured is reduced
Solution Approach 1:
The patent introduces a waveguide structure that extends the light collection path from a two-dimensional aperture plane into a three-dimensional space. The waveguide allows light to travel through an extended path length while maintaining a compact footprint, effectively adding a spatial dimension to the light collection process. This enables increased light capture without requiring a larger aperture area, thus resolving the contradiction between high-speed operation (small aperture) and light collection efficiency.
2Speed
If the detection aperture is reduced to increase operation speed, then the responsivity of photodetectors is impacted
Solution Approach 1:
The waveguide structure serves as an intermediary element between the incident light and the photodetector active area. It collects and concentrates light from a larger effective area and directs it onto the smaller photodetector surface, thereby maintaining high responsivity despite the reduced aperture size required for high-speed operation. The waveguide acts as a light funnel that mediates between the aperture size constraint and the light collection requirement.
3Area of stationary object
If a waveguide structure is introduced to enhance light collection, then the effective optical detecting area increases, but the device complexity increases
Solution Approach 1:
The waveguide structure is integrated with the photodetector device, merging the light collection function with the detection function. Rather than adding a completely separate light collection system, the waveguide is combined with the photodetector substrate and active regions, creating a unified structure that performs both light gathering and signal detection in a single integrated component, thereby minimizing the increase in device complexity.
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 waveguide structure increases the effective optical detecting area and transmission rate of optical signals, improving the overall light collection efficiency and responsivity of photodetectors.
Implementation Method 1
a waveguide structure over the device substrate and the photosensitive region. The waveguide includes a first portion including a first surface with a first width, a second surface with a second width, and a sidewall surface connecting the first surface and the second surface
Data Source
AI summary
A waveguide structure includes a first surface having a first width, a second surface having a second width, the second surface being opposite to the first surface, and a sidewall surface connecting the first surface and the second surface. The first width is greater than the second width.