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Related Concept Videos

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)01:20

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
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Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)01:22

Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)

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Shear on the Horizontal Face of a Beam Element01:16

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Fabrication of High Contrast Gratings for the Spectrum Splitting Dispersive Element in a Concentrated Photovoltaic System
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Compact slanted grating couplers.

Bin Wang, Jianhua Jiang, Gregory Nordin

    Optics Express
    |June 2, 2009
    PubMed
    Summary
    This summary is machine-generated.

    We developed a compact slanted grating coupler (SLGC) for efficient fiber-to-waveguide connections. Optimized using a genetic algorithm, it achieved 80.1% coupling efficiency, simplifying optical systems.

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    Area of Science:

    • Photonics
    • Optical Engineering
    • Nanotechnology

    Background:

    • Vertical fiber-to-waveguide coupling is crucial for integrated optical circuits.
    • Existing methods often require complex intermediate optics, increasing size and cost.
    • Slanted grating couplers offer a potential solution for direct vertical interfacing.

    Purpose of the Study:

    • To design and optimize a compact and highly efficient slanted grating coupler (SLGC).
    • To achieve direct vertical coupling between optical fibers and planar waveguides.
    • To eliminate the need for intermediate optical components.

    Main Methods:

    • Utilized a genetic algorithm-based rigorous design tool for optimization.
    • Employed a strong index-modulated slanted grating structure.
    • Performed rigorous mode analysis to verify design principles.

    Main Results:

    • Optimized a 20-micrometer-long SLGC with a record 80.1% input coupling efficiency.
    • Demonstrated simultaneous satisfaction of phase-matching and Bragg conditions.
    • Confirmed operation with the fundamental leaky mode.

    Conclusions:

    • The proposed SLGC design is compact, efficient, and simplifies fiber-to-waveguide integration.
    • This design eliminates the need for intermediate optics, reducing system complexity.
    • The optimized SLGC is suitable for advanced photonic integrated circuits.