Semiconductor Optical Integrated Device Polarity Flexibility
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Solution Overview
Problem
Existing semiconductor optical integrated devices face challenges with increased manufacturing costs and module complexity due to the need for a separate photodiode chip for monitoring optical output, limited polarity flexibility of the photodiode, and increased electrode terminals when using semi-insulating InP substrates, which also leads to potential deterioration of device characteristics from reactive current.
Innovation Solution
A semiconductor optical integrated device is designed with a conductive substrate, a semi-insulating semiconductor layer, and a photodiode where both anode and cathode electrodes are drawn from the upper surface, and the waveguide and photodiode are separated by the semi-insulating semiconductor layer, enhancing polarity flexibility and reducing reactive current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate photodiode chip is used for monitoring optical output, then the device can perform optical monitoring, but the manufacturing cost increases and the number of assembly steps increases
Solution Approach 1:
The patent integrates the photodiode monitoring unit directly into the same semiconductor substrate as the laser unit, eliminating the need for a separate photodiode chip. This merging of functions into a single integrated device reduces manufacturing complexity and assembly steps while maintaining optical monitoring capability.
Solution Approach 2:
The semiconductor substrate is designed to perform multiple functions: it serves as both the laser unit substrate and the photodiode monitoring unit substrate. This multi-functional design allows a single substrate to replace what would traditionally require separate components, reducing overall device complexity.
2Device complexity
If the cathode serves as ground in the integrated device, then the structure is simplified, but the polarity flexibility is limited when a positive polarity power source is desired
Solution Approach 1:
The patent draws both the anode and cathode electrodes from the upper surface of the photodiode, creating a planar configuration. This dimensional arrangement allows both electrodes to be accessed from the same surface, enabling flexible connection to power sources of either polarity without requiring complex three-dimensional electrode routing.
Solution Approach 2:
The photodiode structure is segmented to provide separate anode and cathode contact regions on the upper surface, allowing independent electrical connections. This segmentation enables the device to accommodate different power source polarities by selectively connecting the appropriate electrodes.
3Reliability
If a semi-insulating InP substrate is used with both anode and cathode on the upper surface, then the photodiode structure is improved, but the number of electrode terminals increases
Solution Approach 1:
The patent combines the laser unit and photodiode monitoring unit onto a single semiconductor substrate, sharing common structural elements and substrate infrastructure. This merging reduces the total number of discrete electrode terminals needed compared to using separate chips for each function.
4Reliability
If the photodiode and laser are electrically separated, then reactive current is suppressed and characteristics are improved, but the device structure becomes more complex
Solution Approach 1:
The patent introduces a semi-insulating semiconductor layer as an intermediary between the conductive substrate and the photodiode. This intermediate layer provides electrical isolation to suppress reactive current while maintaining structural integration, achieving electrical separation without requiring complete physical disconnection of components.
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 allows for improved polarity flexibility of the photodiode, reduces the number of electrode terminals, and suppresses reactive current, thereby enhancing the device's characteristics and operational stability.
Implementation Method 1
the waveguide and the photodiode are separated from each other by the semi-insulating semiconductor layer
Implementation Method 2
a waveguide that is provided on the conductive substrate and guides output light of the laser to the photodiode
Data Source
AI summary
A semiconductor optical integrated device according to the present invention includes a conductive substrate, a laser provided to the conductive substrate, a semi-insulating semiconductor layer provided on the conductive substrate, a photodiode provided on the semi-insulating semiconductor layer and a waveguide that is provided on the conductive substrate and guides output light of the laser to the photodiode, wherein an anode of the photodiode and a cathode of the photodiode are drawn from an upper surface side of the photodiode, and the waveguide and the photodiode are separated from each other by the semi-insulating semiconductor layer.