Tapered Waveguide Concave Structure Reduces Insertion Loss
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Solution Overview
Problem
Existing tapered waveguides with a straight-line structure suffer from significant insertion loss due to rapid changes in effective refractive index in narrower areas and increased length without substantial refractive index changes in wider areas, limiting their miniaturization and efficiency.
Innovation Solution
The tapered waveguide is optimized with a concave structure for shallow-etched strip waveguides, where a narrower area has a longer length to reduce effective refractive index changes and a wider area has a shorter length, maintaining low insertion loss and reducing overall device length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a straight-line structure tapered waveguide is used, then the manufacturing is simple, but the insertion loss is large due to rapid effective refractive index changes in narrower areas
Solution Approach 1:
The patent applies curvature by changing the tapered waveguide structure from a straight-line configuration to a curved configuration. The curved tapered waveguide has a first curved waveguide section and a second curved waveguide section with different curvature radii, which allows for more gradual and controlled changes in the effective refractive index, thereby reducing insertion loss while maintaining manufacturability through standard photolithography and etching processes.
2Area of stationary object
If a straight-line structure tapered waveguide is used, then the structure is compact, but the device length is increased in wider areas where effective refractive index does not change greatly
Solution Approach 1:
The curved tapered waveguide structure enables more efficient space utilization by employing different curvature radii in different sections. The first curved waveguide section has a first curvature radius and the second curved waveguide section has a second curvature radius that is different from the first, allowing the waveguide to achieve the required transition while minimizing both the footprint area and the overall device length simultaneously.
3Device complexity
If a straight-line structure tapered waveguide is used, then the manufacturing process is simple, but the effective refractive index changes dramatically in narrower areas resulting in high insertion loss
Solution Approach 1:
The curved tapered waveguide maintains relatively simple manufacturing processes while improving signal transmission quality through its curved geometry. The different curvature radii in different sections provide more gradual effective refractive index transitions, reducing signal loss and improving transmission reliability without requiring complex manufacturing steps.
Solution Approach 2:
The patent changes the geometric parameters of the tapered waveguide by introducing curvature radii as key design parameters. The first curved waveguide section has a first curvature radius and the second curved waveguide section has a second curvature radius, allowing optimization of the effective refractive index distribution to reduce insertion loss and improve signal transmission quality.
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 design effectively reduces insertion loss and device length, facilitating miniaturization and improving chip integration while maintaining compatibility with CMOS technology.
Implementation Method 1
The waveguide includes a core layer made of a high-refractive-index material and a buried cladding and an upper cladding that are made of low-refractive-index materials
Data Source
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AI summary
A tapered waveguide includes a central waveguide (10) and shallow-etched strip waveguides (20) disposed on both sides of the central waveguide. Each shallow-etched strip waveguide (20) is of a structure with a gradually changing width, and an outline, away from the central waveguide (10) and in a length direction, of the shallow-etched strip waveguide (20) is a concave arc without an abrupt change. An effective refractive index changes slowly and an insertion loss of a device can be effectively reduced. In addition, a wider area of the shallow-etched strip waveguide has a shorter length. In this way, a length of the device is effectively reduced, thereby facilitating miniaturization of the device. A silicon-based chip is further disclosed.