Nonlinear optical characterization of Silicon-Rich Nitride waveguides fabricated using deuterated silane are presented. Fourier Transform Infrared Spectroscopy reveals the absence of Si-H and N-H related bonds known t...
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We propose the novel optimization method for femtosecond laser writing of waveguides in lithium niobate (LN) crystal with low propagation loss. In this method, Raman spectroscopy is used to obtain detailed structural ...
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The Brillouin gain characteristics were demonstrated in two low-loss chalcogenide waveguides. Compared with the Brillouin gain coefficient of 202 m-1W-1 in the As-S spiral waveguide, the gain performance of the Ge-As-...
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A method for the estimation of sheet impedance of thin sample which does not require a direct contact with the sample under test is proposed. The surface impedance is calculated through an inversion procedure exploiti...
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A micro-structured suspended-core waveguide is designed for information transmission at 128 GHz carrier frequency. It is 3D printed using a 45° inclined extruder that enables continuous, length-unlimited fabricat...
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The fast quasi-adiabatic dynamics (FAQUAD) protocol has proven to be an effective approach to provide shortcuts to adiabatic light evolution in optical waveguides, resulting in short and robust devices. However, the F...
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The fast quasi-adiabatic dynamics (FAQUAD) protocol has proven to be an effective approach to provide shortcuts to adiabatic light evolution in optical waveguides, resulting in short and robust devices. However, the FAQUAD approach of homogeneously distributing device adiabaticity only works for a single mode (polarization, wavelength, or spatial mode group) system. We propose an adiabaticity engineering approach to redistribute the adiabaticity of optical waveguides in multi-mode systems. By engineering the adiabaticity distribution using a single control parameter, we obtain shortcuts to adiabaticity in optical waveguides for multi-mode systems. The concept is applied to the design of a compact polarization-independent adiabatic 3-dB coupler on silicon. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
In neutron optics, we analyse the propagation of slow (thermal) neutrons along a semi-infinite waveguide limited by a large repulsive potential (reminding the propagation of light along an optical fibre). We set an id...
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In neutron optics, we analyse the propagation of slow (thermal) neutrons along a semi-infinite waveguide limited by a large repulsive potential (reminding the propagation of light along an optical fibre). We set an ideal case of a straight empty two-dimensional semi-infinite waveguide limited by an infinitely repulsive potential (Dirichlet conditions on its boundaries). The neutron wave function is given through an integral representation involving the incoming wave with energyE, Green's function and certain functions defined on the boundaries. The latter functions follow from the Dirichlet conditions, thereby proposing a new formalism in neutron optics. We develop various approximations (through Fourier and Hilbert transforms) and numerical computations. We get: (a) the expected extinction of the incoming wave for very large penetration into the waveguide, (b) the generation of propagation modes and their number for suitably large penetration, asEincreases, (c) an estimate of the critical angle.
This paper presents a three-dimensional adjoint-based marching scheme for long-range inhomogeneous optical waveguide devices. An efficient numerical propagation computation of an optical waveguide terminated by perfec...
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This paper presents a three-dimensional adjoint-based marching scheme for long-range inhomogeneous optical waveguide devices. An efficient numerical propagation computation of an optical waveguide terminated by perfecdy matched layers is available using our approach. It uses new transmission and reflection operators through a one-way formulation of the complex Helmholtz-PML equation and a design of the transverse and adjoint operators that calculates the coordinates through the biorthogonal of their eigenfunctions in each marching step. In addition, the validity and accuracy of our proposed method are demonstrated by analyzing a buried channel waveguide and a straight waveguide with varying refractive indices. (C) 2020 Optical Society of America
We propose a parallel-plate metasurface waveguide, where duality symmetry is realized by spatially arranging two kinds of metasurfaces with opposite equivalent reactance, inductive and capacitive. Period patch and gri...
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Several schemes for the electrical pumping of dielectric loaded surface plasmon polariton waveguides are analysed. Two schemes that are designed to move the electrical contact away from the plasmon mode are compared t...
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Several schemes for the electrical pumping of dielectric loaded surface plasmon polariton waveguides are analysed. Two schemes that are designed to move the electrical contact away from the plasmon mode are compared to a Schottky contact scheme which has the electrical contact at the same metal/semiconductor interface which supports the surface plasmon mode. One scheme involves transporting carriers from lateral contacts via a thin semiconductor pathway. The other scheme involves burying the electrical contact inside the metal surface and having the surface plasmon mode skip over the break in the metal/semiconductor interface. The Schottky contact scheme is shown to have the best confinement of the surface plasmon mode on the gain medium. However, the other two alternative schemes can be engineered to require significantly less gain to overcome metal losses. Current densities required in the non Schottky contact schemes are found to be compatible with current semiconductor laser electrical contacts.
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