Butt-End Waveguide Coupling for Photodetectors
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Solution Overview
Problem
The coupling efficiency between waveguide and photodetector sections in semiconductor devices is limited due to mismatches in mode profiles and indices, leading to energy loss in electromagnetic wave transmission.
Innovation Solution
A semiconductor device configuration with a waveguide section and an adjoining active section, where a semiconductor detector is disposed on the active section, and a dielectric layer and waveguide structure are formed above the waveguide section adjacent to the detector, enhancing modal overlap and effective index match for improved coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a waveguide and photodetector are fabricated on a single substrate, then integration is achieved, but coupling efficiency is limited due to mode profile and mode index mismatches
Solution Approach 1:
The patent introduces an intermediary waveguide structure with specific mode properties that bridges the mode mismatch between the substrate waveguide and photodetector. This intermediary waveguide acts as a mediator to transform and match the mode profiles, enabling efficient coupling while maintaining integration on a single substrate.
Solution Approach 2:
The patent modifies key parameters of the waveguide structure, including mode profile characteristics and mode index, to achieve better matching between the waveguide and photodetector sections. By adjusting these parameters, the coupling efficiency is improved without sacrificing integration benefits.
2Reliability
If waveguide and photodetector sections are integrated, then device functionality is enhanced, but energy loss occurs due to mode index mismatch
Solution Approach 1:
An intermediary waveguide structure is introduced as a mediator between the substrate waveguide and photodetector. This intermediary structure has optimized mode index and profile characteristics that facilitate efficient energy transfer, reducing energy loss while maintaining the integrated device functionality.
Solution Approach 2:
The waveguide structure employs composite material design with different sections having different refractive index profiles. This composite approach allows optimization of mode index matching at interfaces, thereby reducing energy loss while preserving the integrated photodetector functionality.
3Loss of energy
If mode profile matching is improved, then coupling efficiency increases, but device complexity increases
Solution Approach 1:
The waveguide structure is segmented into distinct sections: a substrate waveguide section, an intermediary waveguide section, and a photodetector section. Each segment has optimized mode profile characteristics, and the segmentation allows independent optimization of each section while maintaining overall coupling efficiency, without excessive complexity increase.
Solution Approach 2:
The patent applies local quality optimization by designing different mode profile characteristics for different sections of the waveguide structure. Each local section is optimized for its specific function, with the intermediary section specifically designed to match modes between the substrate waveguide and photodetector, achieving high coupling efficiency without global 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
This configuration significantly enhances coupling efficiency for both TE and TM modes, reducing energy loss and improving the performance of photodetectors by increasing modal overlap and effective index match.
Implementation Method 1
The waveguide serves as a channel to guide electromagnetic waves into the photodetector by confining the waves to propagate in one dimension in order to minimize loss of energy or power
Implementation Method 2
Semiconductor detectors, such as photodetectors, are sensors that detect light or other electromagnetic energy
Data Source
AI summary
The present disclosure generally relates to semiconductor detectors for use in optoelectronic/photonic devices and integrated circuit (IC) chips, and methods for forming same. The present disclosure also relates to photodetectors integrated with waveguide stacks, more particularly, photodetectors with butt-end coupled waveguides. The present disclosure also relates to methods of forming such structures.