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Fully etched apodized grating coupler on the SOI platform with -0.58 dB coupling efficiency.

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    Researchers developed a novel grating coupler for silicon photonics, achieving record-breaking coupling efficiency. This advancement in silicon-on-insulator (SOI) technology enhances optical device performance.

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    Area of Science:

    • Photonics and optical engineering
    • Integrated optics
    • Nanophotonics

    Background:

    • Silicon-on-insulator (SOI) platform is crucial for integrated photonic circuits.
    • Grating couplers are essential for efficient fiber-to-chip optical coupling.
    • Achieving ultrahigh coupling efficiency (CE) remains a key challenge.

    Purpose of the Study:

    • To design and fabricate an ultrahigh CE fully etched apodized grating coupler.
    • To investigate fabrication error sensitivity and coupling angle dependence.
    • To demonstrate a record CE and analyze device performance.

    Main Methods:

    • Utilized subwavelength photonic crystals for enhanced light confinement.
    • Integrated a bonded aluminum mirror for improved reflectivity.
    • Fabricated the device on a silicon-on-insulator (SOI) platform.
    • Experimentally investigated fabrication tolerances and angular performance.

    Main Results:

    • Achieved a record ultrahigh coupling efficiency (CE) of -0.58 dB.
    • Demonstrated a 3 dB bandwidth of 71 nm.
    • Observed low back reflection, indicating efficient light transfer.
    • Characterized sensitivity to fabrication errors and coupling angle.

    Conclusions:

    • The developed grating coupler offers unprecedented CE for SOI platforms.
    • The design shows robustness against fabrication variations.
    • This technology paves the way for more efficient optical interconnects.