Grating Coupler Waveguide Array Bandwidth
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Solution Overview
Problem
Conventional grating couplers have a low bandwidth, limiting their ability to transmit a wide spectrum of optical signals and meet the requirements of modern optical communication systems.
Innovation Solution
The grating coupler design includes multiple waveguide groups with waveguides of different widths, each corresponding to different effective refractive indexes, allowing for multiple coupling center wavelengths and enhanced normalized transmission spectra, thereby increasing the bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional grating coupler with uniform waveguide width is used, then the coupling efficiency at a specific wavelength is optimized, but the bandwidth is limited to approximately 3.8 THz
Solution Approach 1:
The patent applies local quality by varying the width of individual waveguides within the waveguide array. Each waveguide has a specific width tailored to optimize coupling at a particular wavelength, creating local optimizations across the array that collectively broaden the overall bandwidth while maintaining high coupling efficiency at multiple wavelength points
Solution Approach 2:
The patent implements parameter changes by systematically varying the width parameter of waveguides in the array. This parameter variation creates different effective refractive indexes for each waveguide, which shifts the coupling center wavelength for each waveguide, thereby expanding the total bandwidth coverage from 3.8 THz to over 12.5 THz
2Adaptability or versatility
If multiple waveguides with different widths are introduced to increase bandwidth, then the bandwidth increases to over 12.5 THz, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the grating coupler into multiple independent waveguide units within the array. Each waveguide segment has a specific width optimized for a particular wavelength range, allowing the system to achieve broad bandwidth coverage through the collective operation of segmented elements rather than a single complex structure
Solution Approach 2:
The patent implements universality by designing the waveguide array where each waveguide element serves multiple functions: it acts as an independent coupling element for its optimized wavelength while also contributing to the overall broadband performance of the grating coupler. This multi-functionality allows the system to handle multiple wavelength channels simultaneously without requiring separate dedicated structures for each wavelength
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 significantly increases the bandwidth of the grating coupler, enabling the transmission of a broader range of optical signals and enhancing the amount of information that can be transmitted.
Implementation Method 1
a grating coupler inputs an external optical signal into the silicon-based PIC chip, or outputs an optical signal inside the silicon-based PIC chip outside the silicon-based PIC chip in a diffraction manner
Data Source
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AI summary
A grating coupler and a preparation method thereof are provided. The grating coupler includes a substrate layer (0), a lower confining layer (1), a waveguide core layer (2), and an upper confining layer (3) that are sequentially arranged. The waveguide core layer (2) includes a submicron waveguide (4), a first tapered waveguide (5), and a waveguide array (6). The waveguide array (6) includes at least two waveguide groups, the waveguide group includes at least one waveguide chain, the waveguide chain includes at least two waveguides that have different widths, the waveguides in the waveguide chain are connected to each other, waveguides in the waveguide chains included in a same waveguide group have a same width and a same arrangement structure, and waveguides in the waveguide chains included in different waveguide groups have different widths and/or different arrangement structures. An end of the waveguide chain in the waveguide array (6) is connected to a wide end of the first tapered waveguide (5), and a narrow end of the first tapered waveguide (5) is connected to the submicron waveguide (4). The grating coupler can increase a bandwidth.