Optical Multiplexer Unwanted-Light Waveguides Reduce Reflection
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Solution Overview
Problem
Semiconductor waveguides used in optical multiplexers face challenges in fine processing due to their smaller design size compared to lithium niobate waveguides, leading to increased light reflection and deviations from design shapes.
Innovation Solution
Incorporating unwanted-light waveguides made of semiconductor material that satisfy single-mode conditions, these waveguides are connected to the multi-mode-interference part to increase the interval with the output waveguide, facilitating accurate etching and reducing light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If semiconductor waveguides are used in optical multiplexers, then the device size is reduced (one-tenth or less of lithium niobate waveguides), but the interval between waveguides becomes too narrow, making fine processing through etching difficult and causing shapes to deviate from design
Solution Approach 1:
The invention introduces unwanted-light waveguides as separate, distinct structures from the main signal transmission path. By segmenting the optical circuit into signal waveguides and unwanted-light waveguides, the design can optimize each independently - keeping signal waveguides close for compactness while positioning unwanted-light waveguides far enough away to allow accurate etching and processing
Solution Approach 2:
The unwanted-light waveguides act as intermediary structures that handle higher-order modes separately from the main signal path. This mediator approach allows the system to manage unwanted light without compromising the precision of the main signal waveguides, as the intermediary structures can be positioned and processed independently
2Productivity
If the interval between the main output waveguide and the subsidiary output waveguide is narrowed to reduce device size, then integration is improved, but processing error increases and light reflection increases
Solution Approach 1:
The invention extracts the unwanted-light handling function into separate dedicated waveguide structures. By taking out the higher-order mode management from the main signal path and placing it in separate unwanted-light waveguides positioned at optimized intervals, the system achieves both high integration and low reflection - the main signal waveguides can be closely integrated while the extracted unwanted-light waveguides are positioned to minimize reflection
Solution Approach 2:
The invention applies different spatial configurations to different functional regions: the main signal waveguides are positioned for optimal signal transmission and integration, while the unwanted-light waveguides are positioned at specific intervals optimized for minimizing reflection. Each region has its own local quality optimized for its specific function
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 increased interval allows for precise shaping of waveguides, reducing light reflection and improving the waveform of light, with experimental results showing a 10% improvement in mask margin and reduced light reflection.
Implementation Method 1
a multi-mode-interference part made of a semiconductor material. The multi-mode-interference part has an incoming end surface connected to the input waveguides, and an outgoing end surface opposite to the incoming end surface and connected to the output waveguide
Implementation Method 2
The unwanted-light waveguides each satisfy a single-mode condition... This reduces the waveguide widths of the unwanted-light waveguides when compared to an instance where the unwanted-light waveguides does not satisfy the single-mode condition. Hence, the interval between each unwanted-light waveguide and the output waveguide increases
Data Source
AI summary
Two input waveguides are made of a semiconductor material. One output waveguide is made of a semiconductor material. A multi-mode-interference part is made of a semiconductor material. The multi-mode-interference part has an incoming end surface connected to the input waveguides, and an outgoing end surface opposite to the incoming end surface and connected to the output waveguide. The multi-mode-interference part has a waveguide width wider than the waveguide widths of the input waveguides and the waveguide width of the output waveguide. Two unwanted-light waveguides are made of a semiconductor material. The unwanted-light waveguides are connected to the outgoing end surface of the multi-mode-interference part so as to sandwich the output waveguide. The unwanted-light waveguides each satisfy a single-mode condition.