Resonant Waveguide Photodetector for Quantum Efficiency
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Solution Overview
Problem
Existing photodetectors suffer from low quantum efficiency and low responsivity, along with nonuniform electric field distribution in the absorption region, which reduces responsivity and results in unsatisfactory gain bandwidth product.
Innovation Solution
A photodetector with a resonant waveguide structure is proposed, comprising a substrate, a light absorption layer, and a resonant waveguide structure that includes a first waveguide portion and a second waveguide portion with a circular transmission path, enhancing optical signal coupling to the light absorption layer and improving quantum efficiency and responsivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional photodetector structure is used, then the device is simple, but the quantum efficiency is low and responsivity is low
Solution Approach 1:
The waveguide structure is divided into multiple segments: a first waveguide portion for receiving and transmitting the optical signal, and a second waveguide portion with a circular transmission path for enhancing coupling. This segmentation allows each portion to perform its specific function optimally, improving quantum efficiency while maintaining manageable structural complexity
Solution Approach 2:
The second waveguide portion incorporates a circular transmission path instead of a straight waveguide. This curved geometry enables the optical signal to circulate and couple multiple times with the light absorption layer, significantly enhancing the responsivity and quantum efficiency through repeated interaction opportunities
2Reliability
If a conventional photodetector structure is used, then the device is simple, but the responsivity is low
Solution Approach 1:
The circular transmission path in the second waveguide portion enables continuous circulation of the optical signal. The signal repeatedly passes through the coupling region, maintaining continuous interaction with the light absorption layer. This continuous action increases the number of coupling events and significantly enhances responsivity
Solution Approach 2:
The curved circular geometry of the second waveguide portion creates a compact path that facilitates repeated coupling interactions. The curvature allows the signal to loop back and interact with the absorption layer multiple times within a small space, enhancing responsivity without requiring a proportionally large device footprint
3Reliability
If the light absorption layer is directly coupled with the waveguide, then the structure is simple, but the coupling efficiency is insufficient and quantum efficiency is low
Solution Approach 1:
The coupling structure is segmented into two distinct waveguide portions with different functions: the first portion for signal transmission and the second portion with circular path for enhanced coupling. This segmentation allows optimization of each portion for its specific function, improving overall coupling efficiency
Solution Approach 2:
The circular transmission path in the second waveguide portion creates multiple coupling opportunities by circulating the signal repeatedly near the light absorption layer. This curved geometry enhances the interaction between the waveguide mode and the absorption layer, significantly improving coupling efficiency and quantum efficiency
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 resonant waveguide structure enhances optical signal coupling, increases the number of coupling times, and improves the responsivity of the photodetector, addressing the limitations of existing photodetectors.
Implementation Method 1
The resonant waveguide structure includes a first waveguide portion and a second waveguide portion spaced apart from each other. The first waveguide portion is configured to receive the optical signal and transmit the received optical signal to a first region of the second waveguide portion.
Implementation Method 2
The second waveguide portion further includes a second region configured to couple the optical signal to the light absorption layer
Implementation Method 3
The light absorption layer is located on the substrate and configured for detecting an optical signal
Data Source
AI summary
Disclosed is a photodetector with a resonant waveguide structure, including: a substrate; a light absorption layer located on the substrate and configured for detecting an optical signal; a resonant waveguide structure including a first waveguide portion and a second waveguide portion spaced apart; the first waveguide portion receives the optical signal and transmits the received optical signal to a first region of the second waveguide portion, the second waveguide portion includes a second region for coupling the optical signal to the light absorption layer, and the second waveguide portion provides a circular transmission path for transmission of the optical signal to transmit the optical signal that transmitted to the first region to the second region along part of the circular transmission path and retransmit the optical signal that flows through the second region without being coupled to the light absorption layer to the second region along the circular transmission path.