Segmented Ge Waveguide Photodetector for Faster Carrier Collection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The response speed of Germanium (Ge) waveguide photodetectors in high-speed optical transceivers is limited by the transit time of photogenerated carriers, which is constrained by the distance they travel to reach the electrodes, and this distance cannot be significantly reduced due to process limitations.
Innovation Solution
The photodetector design incorporates segmented optical absorbers positioned according to the offset of the optical signal, aligning with the periodic zigzag pattern of the signal, thereby reducing the travel distance of photogenerated carriers to the edges of the detector, where they can be collected more efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the width of the absorption region is reduced to reduce the travel distance of photogenerated carriers, then the transit time is improved and response speed increases, but process limitations prevent further reduction of the absorption region width
Solution Approach 1:
The absorption region is divided into multiple discrete absorption regions arranged in a periodic pattern along the propagation direction of the optical signal. This segmentation allows carriers to be generated at multiple positions along the propagation path, effectively reducing the maximum distance any carrier must travel to reach an electrode, thereby improving response speed while maintaining a manufacturable overall absorption region width.
Solution Approach 2:
The invention transitions from a single-plane absorption structure to a three-dimensional periodic arrangement of absorption regions. By distributing absorption regions across multiple planes or depths in the substrate, the design reduces the effective carrier travel distance in the lateral direction while maintaining sufficient total absorption volume, thus improving speed without violating process limitations on absorption region dimensions.
2Speed
If the absorption region width is reduced to improve transit time, then the response speed increases, but the absorption efficiency may be compromised
Solution Approach 1:
The absorption region is divided into multiple discrete absorption regions arranged in a periodic pattern along the propagation direction of the optical signal. This segmentation allows carriers to be generated at multiple positions along the propagation path, effectively reducing the maximum distance any carrier must travel to reach an electrode, thereby improving response speed while maintaining a manufacturable overall absorption region width.
Solution Approach 2:
The periodic arrangement of absorption regions ensures continuous interaction between the optical signal and the absorption material along the propagation direction. This continuous distribution of absorption regions maintains high absorption efficiency by ensuring that optical power is consistently absorbed throughout the interaction length, while the segmented structure simultaneously reduces carrier transit distances.
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 enhances the speed of the photodetector by reducing the transit time of photocarriers, improving the response speed and efficiency of the photodetector.
Implementation Method 1
converting the optical data streams into the electrical domain
Data Source
AI summary
A photodetector includes a substrate, a first optical absorber, and a second optical absorber. The first optical absorber is disposed in the substrate along a direction of propagation of an optical signal through the substrate. The first optical absorber is offset in the substrate according to an offset of the optical signal in a direction orthogonal to the direction of propagation. The second optical absorber is disposed in the substrate along the direction of propagation of the optical signal. The second optical absorber is offset in the substrate according to the offset of the optical signal in the direction orthogonal to the direction of propagation.