Porous Semiconductor Waveguide Coupling for Micro-LED Light Transfer
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Solution Overview
Problem
The challenge in photonic systems for intra-chip and inter-chip communication is effectively coupling light emitted by micro-LEDs into waveguides, as LEDs emit optical modes in multiple directions, leading to inefficient coupling and high radiation losses.
Innovation Solution
An optoelectronic system is developed with a stack comprising a porous semiconductor layer and a waveguide, where the second common semiconductor layer ensures refractive index matching between the transducer and the waveguide, minimizing reflected photons, and a porous layer creates index contrast to enhance coupling, while maintaining single-mode propagation for efficient light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an LED is coupled to a waveguide, then inter-chip connection with short distance and low consumption is achieved, but the coupling efficiency is low due to multi-directional light emission
Solution Approach 1:
The patent employs a porous layer formed in the semiconductor structure to modify the refractive index distribution. The porous region creates an effective refractive index that is lower than the surrounding solid semiconductor material, enabling better optical mode matching between the LED and waveguide. This porous structure acts as an optical adapter that captures multi-directional light emission from the LED and redirects it into the waveguide mode, significantly improving coupling efficiency without adding complex external optical components.
Solution Approach 2:
The patent modifies the refractive index parameter of the semiconductor layer by creating a porous structure with controlled porosity. By adjusting the degree of porosity, the effective refractive index can be tuned to optimize the modal overlap between the LED emission patterns and the waveguide modes. This parameter change approach allows the same semiconductor material to serve both electrical and optical functions, resolving the contradiction between coupling efficiency and device complexity.
2Loss of energy
If a common semiconductor layer is used between transducer and waveguide, then refractive index matching is achieved reducing reflected photons, but index contrast needed for waveguide function is reduced
Solution Approach 1:
The patent applies local quality modification by creating a porous layer only in specific regions where optical coupling is needed, while maintaining the solid semiconductor structure in regions where waveguide confinement is critical. The porous layer is positioned at the interface between the LED and waveguide, providing local refractive index matching to reduce reflections, while the waveguide core maintains its solid structure to ensure proper optical confinement. This spatial differentiation resolves the contradiction between reducing reflected photons and maintaining waveguide function.
Solution Approach 2:
The patent creates a composite semiconductor structure combining porous and solid regions within the same layer system. The composite structure consists of a porous semiconductor layer adjacent to the LED, transitioning to a solid semiconductor waveguide core. This composite material approach allows the system to simultaneously achieve refractive index matching for reduced reflections in the coupling region and sufficient index contrast for waveguide confinement in the transmission region, resolving the apparent contradiction between the two requirements.
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 maximizes the coupling between the photoelectric transducer and the waveguide, reducing radiation losses and enabling high-speed, low-consumption communication by aligning the refractive indices and optimizing modal overlap, thus improving communication efficiency.
Implementation Method 1
the first porous layer of semiconductor material... the waveguide comprising a second portion of the second layer adjacent to the first portion and arranged on a second portion of the first porous layer
Implementation Method 2
a zone comprising one or more quantum wells... the photoelectric transducer comprising a first portion of the first porous layer, a first portion of the second layer, at least a first portion of the zone comprising the quantum well(s)
Data Source
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AI summary
One aspect of the invention relates to an optoelectronic system (1) comprising a photoelectric transducer (11) configured to emit or receive optical waves and a waveguide (12) configured to guide the waves emitted by the transducer (11) or to guide the waves to the transducer (11), the optoelectronic system (1) comprising a stack successively comprising: - a first porous layer (111) of semiconductor material doped according to a first type of doping, - a second layer (112) of semiconductor material doped according to the first type of doping and weakly doped compared to the semiconductor material of the first layer (111), - a region (113) comprising quantum wells, - a third layer (116) of semiconductor material doped according to a second type of doping opposite to the first type, the photoelectric transducer (11) comprising a first portion (111a) of the first porous layer (111),a first portion (112a) of the second layer (112), at least a first portion (113a) of the area comprising the quantum well(s) and at least a first portion (116a) of the third layer (116); the waveguide (12) comprising a second portion (112b) of the second layer (112) adjacent to the first portion (112a) and disposed on a second portion (111b) of the porous first layer (111).