scholarly journals Fully three-dimensional analysis of a photonic crystal assisted silicon on insulator waveguide bend

2018 ◽  
Vol 32 (31) ◽  
pp. 1850344 ◽  
Author(s):  
N. Eti ◽  
Z. Çetin ◽  
H. S. Sözüer
Keyword(s):  
Photonic Crystal ◽  
Numerical Study ◽  
Fdtd Method ◽  
Three Dimensional ◽  
Silicon On Insulator ◽  
Geometrical Parameters ◽  
Low Loss ◽  
Bending Loss ◽  
Difference Time ◽  
Waveguide Bend

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.

scholarly journals Design of photonic crystal horn antenna for transverse electric modes

2020 ◽  
Vol 50 (3) ◽  
Author(s):  
Ehsan Beiranvand ◽  
Mohammad Danaie ◽  
Majid _Afsahi
Keyword(s):  
Photonic Crystal ◽  
Low Cost ◽  
Hexagonal Lattice ◽  
Fdtd Method ◽  
Horn Antenna ◽  
Frequency Range ◽  
Low Loss ◽  
Circular Holes ◽  
Two Dimensional Photonic Crystal ◽  
Difference Time

In this paper, by modifying defects in a photonic crystal lattice, a two-dimensional photonic crystal horn antenna is designed. The photonic crystal used for this purpose is composed of a hexagonal lattice of circular holes in a dielectric slab. The results of this paper allow us to design a photonic crystal antenna capable of separating TE and TM modes. The designed structure has a very simple design that allows low cost fabrication. The structure is numerically simulated using a finite-difference time-domain (FDTD) method. Its wide bandwidth, its low loss and the ability to transmit waves at a terahertz frequency range are the antenna’s main advantages. The return loss for the frequency range of 180 to 215 THz is from –6.63 to –28.3 dB. Moreover, a 35 THz bandwidth is obtained for this structure.

Q-BOR–FDTD method for solving Schrodinger equation for rotationally symmetric nanostructures with hydrogenic impurity

2022 ◽  
Author(s):  
Arezoo Firoozi ◽  
Ahmad Mohammadi ◽  
Reza Khordad ◽  
Tahmineh Jalali
Keyword(s):  
Schrödinger Equation ◽  
Analytical Solutions ◽  
Schrodinger Equation ◽  
Fdtd Method ◽  
Three Dimensional ◽  
Test Cases ◽  
Body Of Revolution ◽  
Hydrogenic Impurity ◽  
Rotationally Symmetric ◽  
Difference Time

Abstract An efficient method inspired by the traditional body of revolution finite-difference time-domain (BOR-FDTD) method is developed to solve the Schrodinger equation for rotationally symmetric problems. As test cases, spherical, cylindrical, cone-like quantum dots, harmonic oscillator, and spherical quantum dot with hydrogenic impurity are investigated to check the efficiency of the proposed method which we coin as Quantum BOR-FDTD (Q-BOR-FDTD) method. The obtained results are analysed and compared to the 3-D FDTD method, and the analytical solutions. Q-BOR-FDTD method proves to be very accurate and time and memory efficient by reducing a three-dimensional problem to a two-dimensional one, therefore one can employ very fine meshes to get very precise results. Moreover, it can be exploited to solve problems including hydrogenic impurities which is not an easy task in the traditional FDTD calculation due to singularity problem. To demonstrate its accuracy, we consider spherical and cone-like core-shell QD with hydrogenic impurity. Comparison with analytical solutions confirms that Q-BOR–FDTD method is very efficient and accurate for solving Schrodinger equation for problems with hydrogenic impurity

Effect of Metal Intercalating on Transmission Characteristics of One-Dimensional Photonic Crystal

2011 ◽  
Vol 418-420 ◽  
pp. 679-683
Author(s):  
Bei Jia He ◽  
Xin Yi Chen ◽  
Jian Bo Wang ◽  
Jun Lu ◽  
Jian Chang ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Plasma Frequency ◽  
Fdtd Method ◽  
Transmission Characteristics ◽  
Material Characteristic ◽  
One Dimensional ◽  
Dimensional Photonic Crystal ◽  
Simulation Results ◽  
The One ◽  
Difference Time

To expand the bandgap's width of the one-dimensional photonic crystal, a crystal named SiO2/Metal/MgF2 is formed by joining some metals into the crystal SiO2/MgF2. Furthermore the Finite Difference Time Domain (FDTD) method is used to explore the metals' influence on the crystal's transmission characteristics. The simulation results show that the metals joined could expand the width of the one-dimensional photonic crystal's bandgap effectively and the bandgap's width increases when the metals' thickness increases. Meanwhile the bandgap's characteristic is affected by the metals' material-characteristic. The higher the plasma frequency is, the wider the bandgap's width will be and the more the number of the bandgaps will be. On the other hand, the metals' damping frequency has no significant effect on the bandgap, but would make the bandgap-edge's transmittance decrease slightly.

Incorporation of GPR data into characterization of the bitumen filled cracks in pavements: Lab and numerical study

2020 ◽  
Author(s):  
Mezgeen Rasol ◽  
Vega Pérez Gracia ◽  
Mercedes Solla ◽  
Jorge C. Pais ◽  
Francisco M. Fernandes ◽  
...  
Keyword(s):  
Computational Models ◽  
Numerical Study ◽  
Fdtd Method ◽  
Asphalt Pavements ◽  
The Road ◽  
Rigid Pavements ◽  
Temporary Solution ◽  
Ground Penetrating ◽  
Difference Time

<p>Road pavements are subject to a range of problems due to traffic and temperature variations </p><p>producing cracks that propagate to the pavement surface. Cracks need to be assessed to avoid </p><p>deterioration and provide confidence in the functioning of the road system. Cracks are usually </p><p>maintained after visual inspection by filling with bitumen as a first rehabilitation technique to </p><p>avoid further deterioration and absorbing water leakages. Although this temporary solution does </p><p>not extend the pavement life cycle it can help to avoid additional problems occurring within the</p><p>pavement. This work is proposed to aid the development of understanding and characterization</p><p>of cracks filled with bitumen in both rigid and asphalt pavements.</p><p>This study reports on the results of several laboratory experiments that were performed to </p><p>explore the capability of Ground Penetrating Radar (GPR) in the assesment of bitumen-filled </p><p>cracks in both rigid and asphalt pavements, respectively. These tests were focused on the </p><p>analysis of cracking filled with bitumen using a GPR system equipped with a ground-coupled </p><p>antenna with a 2.3 GHz central frequency, and varying the antenna orientation with respect to the </p><p>crack axis.</p><p>Results showed the variation in characterization and changes in amplitude that could be expected </p><p>when analysing bitumen-filled cracks in concrete and asphalt specimens, dependent upon the </p><p>antenna orientation being used; GPR B-scans were compared to images from computational </p><p>models using a Finite-Difference Time-Domain (FDTD) method-based software package </p><p>(gprMax2D). Additionally, a field survey carried out provided images consistent with the</p><p>comparable conditions of the lab tests. The results of this work proved the capability of the GPR</p><p>method to detect and characterize cracks filled with bitumen in pavements across a range of </p><p>crack dimensions and pavement types.</p><p> </p><p>Keywords</p><p>GPR, NDT, Rigid pavements, Asphalt Pavements, Cracks, Computational models, Target orientation,</p><p>Pavement assessmen</p>

Characteristics of Slow Light in a Photonic Crystal Coupled-Cavity Waveguide

2014 ◽  
Vol 887-888 ◽  
pp. 437-441
Author(s):  
Chang Xin Zhang ◽  
Xing Sheng Xu ◽  
Wei Xi
Keyword(s):  
Photonic Crystal ◽  
Group Velocity ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Slow Light ◽  
Fdtd Method ◽  
Photonic Crystal Waveguide ◽  
Difference Time ◽  
Coupled Cavity ◽  
Coupled Cavity Waveguide

A two-dimensional (2D) triangular lattice photonic crystal coupled-cavity waveguide is designed and optimized. The transmission spectrum of the PC waveguide with TE polarization is calculated by using the finite-difference time-domain (FDTD) method, and the group velocity of c/131.18 at the wavelength is obtained. Through optimizing the parameters of photonic crystal waveguide, different resonance length are obtained by changing the number of the continous air holes. The smallest group velocity is obtained to be c/2209 in the coupled-cavity waveguide with 15 air holes. The mechanism of slow light in the coupled-cavity waveguide of photonic crystal is analyzed.

Design and Fabrication of Novel Photonic Crystal Waveguide Consisting of Si-Ion Implanted SiO2 Layers

2010 ◽  
Vol 459 ◽  
pp. 168-172 ◽  
Author(s):  
Amarachukwu Valentine Umenyi ◽  
Masashi Honmi ◽  
Shinya Kawashiri ◽  
Teruyoshi Shinagawa ◽  
Kenta Miura ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Fdtd Method ◽  
Design Parameters ◽  
Photonic Crystal Waveguide ◽  
Atomic Force ◽  
Telecommunication Wavelength ◽  
Two Dimensional Photonic Crystal ◽  
Difference Time ◽  
Si Ion Implantation ◽  
Ion Implanted

In this paper, we designed and fabricated two-dimensional photonic crystal (2-D PhC) consisting of the silicon ion (Si-ion) implanted silicon dioxide (SiO2) layers. The PhC design parameters based on the telecommunication wavelength (λ=1.55 µm) were obtained using finite-difference time-domain (FDTD) method. By analyzing the samples fabricated using different fabrication approach; we found a suitable fabrication method for 2-D PhCs based on the Si-ion implanted SiO2 layers. We have analyzed the fabricated sample using atomic force microscope (AFM) and annealing temperature and time were optimized in order to recover the damage done by Si-ion implantation. The implantation of Si-ion into SiO2 with the process of 2-D PhCs structure can effectively guide light inside such structure, which can easily be integrated into the existing silicon technology for directing light from one part of the chip to the other.

2x2 Optical Switch Based on Silicon-on-Insulator Microring Resonator

2011 ◽  
Vol 378-379 ◽  
pp. 531-534
Author(s):  
B. Mardiana ◽  
Hanim Abdul Razak ◽  
H. Hazura ◽  
S. Shaari ◽  
P. Susthitha Menon ◽  
...  
Keyword(s):  
Optical Switch ◽  
Free Spectral Range ◽  
Fdtd Method ◽  
Single Mode ◽  
Microring Resonator ◽  
Silicon On Insulator ◽  
Electric Signal ◽  
Compact Size ◽  
Near Future ◽  
Difference Time

In near future, silicon-on-insulator (SOI) microring resonator are expected to be basic components for wavelength filtering and switching due to their compact size and wide free spectral range (FSR). In this paper, a 2X2 optical switch by using active microring resonator is proposed. The switch is consists of second order serially cascaded microring coupled to a pair of waveguide. The ON/OFF state of the design is control by electric signal which will vary the refractive index. The device is design to operate at 1.55µm wavelength. With a 500nm x 200nm rib dimensions, the design is proven to have single mode behaviour. Finite-Difference Time-Domain (FDTD) method simulation by RSOFT software is use to characterize the device performance. The results show that the 2X2 optical switch proposed can be an efficient device to be functioning in WDM application.

Effects of the Shape of a Nozzle With Chevrons on the Dynamics of Turbulent Impinging Jet

2016 ◽  
Author(s):  
Sadek Horra ◽  
Zoubir Nemouchi ◽  
Lyes Khezzar
Keyword(s):  
Numerical Study ◽  
Three Dimensional ◽  
Impinging Jet ◽  
Point Of View ◽  
Geometrical Parameters ◽  
Free Jet ◽  
Fundamental Point ◽  
Nozzle Shape ◽  
Heat And Fluid Flow ◽  
Plate Distance

This work is a numerical study of a turbulent impinging jet issuing from a nozzle with chevrons. The Reynolds number based on the jet exit velocity and nozzle diameter is equal to 5000 corresponding to a low Mach number of 0.0057 at the nozzle exit. The main objectives of the investigation, inspired by the work of Violato et al. (Int. J. of Heat and Fluid Flow, 37, 2012), are to highlight, from a fundamental point of view, the effects of the nozzle shape and the nozzle-to-plate distance on the mean parameters characterizing the dynamics of the flow in question. The nozzle configurations considered are a circular nozzle without chevrons and nozzles provided with 4 and 6 chevrons. The nozzle-to-plate distance ranges from 2 to 6 nozzle diameters. All the other flow conditions and geometrical parameters used in the different cases treated are identical. Interesting features of the flow are revealed by the obtained results of averaged three-dimensional fields of velocity and turbulent kinetic energy, particularly close to the wall. An attempt is made to bring additional insight into the phenomena in the free jet, the impingement region and the wall jet when using 4, 6 and no chevrons, for different nozzle-to-plate distances.

Design Two Dimensional Nanocavity Photonic Crystal Biosensor Detection in Malaria

2018 ◽  
Vol 6 (6) ◽  
pp. 16 ◽  
Author(s):  
Varsha Sharma ◽  
Vijay Laxmi Kalyani
Keyword(s):  
Photonic Crystal ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Fdtd Method ◽  
Expansion Method ◽  
Two Dimensional ◽  
Plane Wave Expansion ◽  
Plane Wave Expansion Method ◽  
Output Terminal ◽  
Difference Time

In this paper we design a two dimensional (2-D) photonic crystal based biosensor implemented by linear waveguide and nanocavity detection in malaria. The bio molecules such as a red blood cell, infected red blood cell, trapped inside the nanocavity cause transmission shift at the output terminal.  The sensing mechanism of biosensor is change in refractive index of analytes. The layout biosensor is consists a linear waveguide with a nanocavity in square symmetry For the proposed photonic based biosensor, the band gap from 2210nm to 1420 nm and input wavelength of 1550nm are used in this design. The simulation results have analysed by using the finite difference time domain (FDTD) method, bandgap calculation is performed using plane wave expansion method.

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