Physics / Fizik

Permanent URI for this collectionhttps://hdl.handle.net/11147/6

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Publication Index: search.filters.publicationIndex.ScopusSubject: search.filters.subject.Optical waveguides

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  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Fully Three-Dimensional Analysis of a Photonic Crystal Assisted Silicon on Insulator Waveguide Bend
    (World Scientific Publishing, 2018) Eti, Neslihan; Çetin, Zebih; Sözüer, Hüseyin Sami
    A detailed numerical study of low-loss silicon on insulator (SOI) waveguide bend is presented using the fully three-dimensional (3D) finite-difference time-domain (FDTD) method. The geometrical parameters are optimized to minimize the bending loss over a range of frequencies. Transmission results for the conventional single bend and photonic crystal assisted SOI waveguide bend are compared. Calculations are performed for the transmission values of TE-like modes where the electric field is strongly transverse to the direction of propagation. The best obtained transmission is over 95% for TE-like modes.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 12
    High Transmission Through a 90° Bend in a Polarization-Independent Single-Mode Photonic Crystal Waveguide
    (The Optical Society, 2015) Erol, Adem Enes; Sözüer, Hüseyin Sami
    We propose a polarization-independent single-mode waveguide, using a two-dimensional square photonic crystal with a complete band gap. The waveguide is tuned such that both TE and TM modes have the same group velocity and zero group velocity dispersion at the centergap frequency. We also present results for a 90° bend with transmission values of 98% for both modes.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 6
    Hartree-Fock Approximation of Bipolaron State in Quantum Dots and Wires
    (Springer Verlag, 2010) Senger, Ramazan Tuğrul; Kozal, B.; Chatterjee, A.; Erçelebi, Atilla
    The bipolaronic ground state of two electrons in a spherical quantum dot or a quantum wire with parabolic boundaries is studied in the strong electron-phonon coupling regime. We introduce a variational wave function that can conveniently conform to represent alternative ground state configurations of the two electrons, namely, the bipolaronic bound state, the state of two individual polarons, and two nearby interacting polarons confined by the external potential. In the bipolaron state the electrons are found to be separated by a finite distance about a polaron size. We present the formation and stability criteria of bipolaronic phase in confined media. It is shown that the quantum dot confinement extends the domain of stability of the bipolaronic bound state of two electrons as compared to the bulk geometry, whereas the quantum wire geometry aggravates the formation of stable bipolarons. © 2010 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.