Asymmetric Taper 2D Grating Coupler for Reduced Power Loss
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Solution Overview
Problem
Conventional two-dimensional grating couplers face significant power loss due to mismatched dimensions between waveguides and optical fibers, requiring complex designs that consume hardware resources and simulation time to optimize coupling efficiency.
Innovation Solution
The design incorporates asymmetric triangle taper structures in a two-dimensional grating coupler, with simulated beam propagation using the plane wave expansion method to determine optimal taper dimensions and shifts for efficient light coupling, minimizing power loss across different wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional symmetric taper structures are used in 2D grating couplers, then the design is simpler to manufacture, but power loss increases and coupling efficiency decreases
Solution Approach 1:
The patent applies asymmetry by designing non-symmetric taper structures where the first and second tapers have different shapes, sizes, or orientations. Specifically, the tapers are configured with asymmetric parameters such as different widths, lengths, or angles relative to the waveguide and grating regions, allowing optimized light coupling that reduces power loss while maintaining manufacturability through defined geometric parameters.
2Productivity
If complicated 2D grating designs are used to match taper output field, then coupling efficiency improves, but hardware resources and simulation time increase
Solution Approach 1:
The patent applies parameter changes by systematically varying taper parameters (width, length, angle, position) and grating parameters (period, depth, fill factor) to optimize coupling efficiency. The design uses defined geometric parameters that can be adjusted to match different waveguide and fiber configurations, achieving high coupling efficiency without requiring excessively complex designs that would increase simulation time and hardware resources.
3Ease of manufacture
If symmetric taper structures are used, then manufacturing is easier, but light coupling efficiency is reduced due to dimension mismatch
Solution Approach 1:
The patent applies local quality by creating different taper structures at different locations within the device. The first taper structure has specific geometric properties optimized for coupling light from the first waveguide, while the second taper structure has different properties optimized for the second waveguide. This localized optimization allows each taper to be efficiently manufactured with its specific geometry while achieving high overall coupling efficiency for the device.
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 approach enhances light coupling efficiency by optimizing taper shapes and dimensions based on incident angles and fiber positions, reducing power loss and improving overall optical coupling performance.
Implementation Method 1
Optical gratings are frequently used to couple light between a waveguide and an optical fiber
Data Source
AI summary
Disclosed are apparatus and methods for optical coupling. In one example, a method for forming an optical coupler, includes: forming an insulation layer on a semiconductor substrate; epitaxially growing a semiconductor material on the insulation layer to form a semiconductor layer; etching, according to a predetermined pattern, the semiconductor layer to form: an array of etched holes in the semiconductor layer to form a grating region, a first taper structure extending from a first side of the grating region, wherein a shape of the first taper structure in the semiconductor layer is a first triangle that is asymmetric about any line perpendicular to the first side of the grating region, and a second taper structure extending from a second side of the grating region, wherein a shape of the second taper structure in the semiconductor layer is a second triangle that is asymmetric about any line perpendicular to the second side of the grating region, wherein the first side and the second side are substantially perpendicular to each other; and depositing a dielectric material into the array of etched regions to form an array of scattering elements in the semiconductor layer, wherein the scattering elements are arranged to form a two-dimensional (2D) grating.