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    Paper Review: "Endlessly Single-Mode Photonic Crystal Fiber"

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    bobbyy222
    The document summarizes research on a photonic crystal fiber that enables single mode propagation over a wide wavelength range from 458-1550 nm. The fiber consists of a hexagonal array of air holes in silica with a single defect site at the center that acts as the core. It guides light through total internal reflection from the effective index contrast between the core and cladding, rather than a photonic bandgap effect. The fiber is fabricated by drilling and stacking silica rods in a hexagonal structure then drawing it while varying the spacing to optimize the optical properties. It was found to have a strongly peaked Fourier transform and invariant performance under bending or coupling conditions.

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    Paper Review: "Endlessly Single-Mode Photonic Crystal Fiber"

    Uploaded by

    bobbyy222
    53 views13 pages
    The document summarizes research on a photonic crystal fiber that enables single mode propagation over a wide wavelength range from 458-1550 nm. The fiber consists of a hexagonal array of air holes in silica with a single defect site at the center that acts as the core. It guides light through total internal reflection from the effective index contrast between the core and cladding, rather than a photonic bandgap effect. The fiber is fabricated by drilling and stacking silica rods in a hexagonal structure then drawing it while varying the spacing to optimize the optical properties. It was found to have a strongly peaked Fourier transform and invariant performance under bending or coupling conditions.

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    Final presentation.pptx

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    The document summarizes research on a photonic crystal fiber that enables single mode propagation over a wide wavelength range from 458-1550 nm. The fiber consists of a hexagonal array of air holes in silica with a single defect site at the center that acts as the core. It guides light through total internal reflection from the effective index contrast between the core and cladding, rather than a photonic bandgap effect. The fiber is fabricated by drilling and stacking silica rods in a hexagonal structure then drawing it while varying the spacing to optimize the optical properties. It was found to have a strongly peaked Fourier transform and invariant performance under bending or coupling conditions.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    53 views13 pages

    Paper Review: "Endlessly Single-Mode Photonic Crystal Fiber"

    Uploaded by

    bobbyy222
    The document summarizes research on a photonic crystal fiber that enables single mode propagation over a wide wavelength range from 458-1550 nm. The fiber consists of a hexagonal array of air holes in silica with a single defect site at the center that acts as the core. It guides light through total internal reflection from the effective index contrast between the core and cladding, rather than a photonic bandgap effect. The fiber is fabricated by drilling and stacking silica rods in a hexagonal structure then drawing it while varying the spacing to optimize the optical properties. It was found to have a strongly peaked Fourier transform and invariant performance under bending or coupling conditions.

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    Paper Review: “Endlessly single-mode photonic crystal

    fiber”

    Guided Waves Final Presentation


    By
    Characteristics
    • 2D hexagonal air/silica photonic
    crystal
    • Sub-wavelength holes and a central
    defect site
    • Single low-loss mode: 458-1550 nm
    • Wavelength-dependent effect
    cladding index
    Fig. 1. Scanning electron micrograph of the photonic
    crystal fiber.
    Characteristics
    • 2D hexagonal air/silica photonic
    crystal
    • Sub-wavelength holes and a central
    defect site
    • Single low-loss mode: 458-1550 nm
    • Total Internal Reflection from
    effective index contrast
      1. Scanning electron micrograph of the photonic
    Fig.
    • Not a photonic bandgap effect crystal fiber.
    38 m flat-to-flat
    2.3 m pitch
    4.6 m core region
    0.2-12 m holes
    Fabrication
    1. Drill a 16mm hole in a 30 mm diameter silica rod

    Silica Rods:
    https://www.heraeus.com/en/hqs/products_hqs/optical_fibe
    r/rods_fiber/rods_optical_fiber_fused_silica.aspx
    Fabrication
    1. Drill a 16mm hole in a 30 mm in diameter silica rod
    2. Mill flats to form hexagonal rod

    Silica Rods:
    https://www.heraeus.com/en/hqs/products_hqs/optical_fibe
    r/rods_fiber/rods_optical_fiber_fused_silica.aspx
    Fabrication
    1. Drill a 16mm hole in a 30 mm in diameter silica rod
    2. Mill flats to form hexagonal rod
    3. Stretch at 2000o C to a diameter of 0.8 mm using fiber drawing tower

    Silica Rods: Drawing Tower Figures:


    https://www.heraeus.com/en/hqs/products_hqs/optical_fibe https://www.thorlabs.com/NewGroupPage9_PF.
    r/rods_fiber/rods_optical_fiber_fused_silica.aspx cfm?ObjectGroup_ID=6832
    Fabrication
    1. Drill a 16mm hole in a 30 mm in diameter silica rod
    2. Mill flats to form hexagonal rod
    3. Stretch at 2000o C to a diameter of 0.8 mm using fiber drawing tower
    4. Stack together to form honeycomb structure

    Silica Rods: Drawing Tower Figures:


    https://www.heraeus.com/en/hqs/products_hqs/optical_fibe https://www.thorlabs.com/NewGroupPage9_PF.
    r/rods_fiber/rods_optical_fiber_fused_silica.aspx cfm?ObjectGroup_ID=6832
    Fabrication
    •   Drill a 16mm hole in a 30 mm in diameter silica rod
    1.
    2. Mill flats to form hexagonal rod
    3. Stretch at 2000o C to a diameter of 0.8 mm using fiber drawing tower
    4. Stack together to form honeycomb structure
    5. Draw bundle to achieve 50 m core spacing
    6. Draw bundle again to achieve 2 m core spacing

    Silica Rods: Drawing Tower Figures:


    https://www.heraeus.com/en/hqs/products_hqs/optical_fibe https://www.thorlabs.com/NewGroupPage9_PF.
    r/rods_fiber/rods_optical_fiber_fused_silica.aspx cfm?ObjectGroup_ID=6832
    Performance

    • Near field contour plot Strongly peaked Fourier Transform of the pattern
    • 632.8 nm
    • Scanning electron micrograph
    • Invariant under various fiber coupling or
    bending conditions
    Step index fiber
    Core
    - Cylindrical traveling waves

    https://www.rpi.edu/dept/phys/ScIT/InformationTransfer/reflrefr/rr_content/fibers_20.html

    - High index core, low index cladding – guiding Cladding


    - Cylindrical decaying wave
    through total internal reflection
    - Cylindrical symmetry

      determines number of guided modes


    For single mode fiber, V < 2.405

    depends on , how to make single mode for broad wavelength range?

    http://mathworld.wolfram.com/BesselFunctionoftheFirstKind.html
    How to make wide single-mode range? Effective index

    Effective index of the cladding


    - Index in the cladding weighted by the
    intensity distribution of light
    - Shorter wavelengths – fields more
    concentrated in silica region, avoiding holes in
    the cladding
    Silica core - Longer wavelengths – fields cannot avoid air
    holes as completely -> lowers effective index

     
    Intensity profile High index silica region
    Low index air holes
    Longer wavelengths Compensated by lower
    effective index

    Not relying on photonic bandgap guiding!


    V ends up being nearly constant across wide
    wavelength range (337 – 1550 nm)
    https://www.codeseeder.com/examples/photonic-crystal-fiber/
    Recent Developments
    Sources
    • J. C. Knight, T. A. Birks, P. St. J. Russell, and D. M. Atkin, "All-silica
    single-mode optical fiber with photonic crystal cladding," Opt. Lett.
    21, 1547-1549 (1996)
    • T. A. Birks, J. C. Knight, and P. St. J. Russell, "Endlessly single-mode
    photonic crystal fiber," Opt. Lett. 22, 961-963 (1997)

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