Yuh-Sien Sun

High birefringence photonic crystal fiber with a complex unit cell of asymmetric elliptical air hole cladding

High birefringence induced by elliptical air hole photonic crystal fibers (EHPCFs) is analyzed numerically using the finite-element method. Statistical correlations between the birefringence and the various parameters are obtained. We found that the complex elliptical air hole is better than that of a circular one to obtain high birefringence in photonic crystal fibers. Our suggested structures can considerably enhance the birefringence in EHPCFs and show that the birefringence can be as high as 1.1294 x 10(-2), which is higher than the birefringence obtained from conventional step-index fiber (5 x 10(-4)), circular air holes PCF (3.7 x 10(-3)), and elliptical hollow PCF (2.35 x 10(-3)).

Highly Birefringent Index-Guiding Photonic Crystal Fiber with Squeezed Differently Sized Air-Holes in Cladding

We propose a novel high-birefringence index-guiding photonic crystal fiber (PCF). This PCF is composed of a solid silica core and a cladding with two differently sized squeezed elliptical air-holes. The mode birefringence of a fundamental mode in such PCFs is analyzed numerically by the finite-element method. Numerical results reveal that an extraordinarily high modal birefringence at the excitation wavelength of λ=1550 nm, 2.6×10-2, is acquired. The contributions of the cladding with two different sizes of air-hole ellipticity, the center-to-center distance between the air-holes, and the the number of cladding rings as well as the confinement loss to the birefringence are systematically evaluated. The evolution of birefringence with the structural variations shows that our highly birefringent fiber can be designed in a controlled manner.

Structurally and materially sensitive hybrid surface plasmon modes in periodic silver-shell nanopearl and its dimer arrays

We numerically investigate the surface plasmon resonance (SPR) mode patterns in periodic silver-shell nanopearl arrays and its dimer arrays with the core relative permittivities filled inside the dielectric holes (DHs) by means of finite element method with three-dimensional calculations. Numerical results of resonant wavelengths corresponding to the effects of different period of unit cells, radii of DHs, illumination wavelengths, field propagation, electrical field stream lines, charge distributions, charge densities, half- body charge densities, and the DH core relative permittivities of periodic silver-shell nanopearls are also reported. It can be seen that the periodic silver-shell nanopearl arrays and its dimer arrays with DHs exhibit tunable SPR modes corresponding to the bonding and anti-bonding modes, respectively, that are not observed for the solid silver cases with the same volume. These results are crucial in designing localized SPR sensors and other optical devices based on periodic metal nanoparticle array structures.

Numerical Analysis on Birefringence of Photonic Crystal Fiber by Tuning Patterns and Infiltrating Materials of Innermost Air Holes

In this paper, we give a numerical analysis of a novel high-birefringence and low-confinement loss index-guiding photonic crystal fiber (PCF) using the finite element method by tuning patterns and filling the medium of innermost air holes. This PCF is composed of a solid silica core surrounded by six elliptical air holes and a cladding that consists of binary unit cells. The novelty of the proposed PCF structures is that the large elliptical air holes closest to the core have been rotated in different ways. Results show that the asymmetry in PCF cladding and the area of the PCF core are the key factors for determining the localization extent of the transverse mode. Modal birefringence values and confinement loss at the excitation wavelength of λ=1.55 µm can be easily achieved at a magnitude of the order of 10-2 and at less than 0.39 dB/km, respectively. From the viewpoint of numerical analysis, the effects of a material [with a refractive index <1 (i.e., a metamaterial)] on birefringence infiltrating into small (100–280 nm) innermost air holes, which are reported for the first time here, are also considered.

Analysis of dispersion properties of elliptic air hole photonic crystal fiber

The two dimensional with a triangular-lattice cross sectional pattern of elliptic air holes photonic crystal fiber (PCF) is investigated in detail by use of plan wave expansion (PWE) method. Using PWE method, the dependence of dispersion on structure parameters is calculated. We compared the dispersion relations between the circular air holes PCF and the elliptic one. We find that the flatter dispersion curve and single mode in PCF can be realized by adjusting the width and the holes pitch. The single mode can be obtained by rotating the angle of elliptic air hole and two modes will become one mode. As an example, how to design the structure parameters for engineering the chromatic dispersion of elliptic air holes PCF is demonstrated.

High-Throughput Dickson Basis Multiplier with a Trinomial for Lightweight Cryptosystems

In this study, the authors propose a high-throughput systolic Dickson basis multiplier over GF(2 m ). Use of the Dickson basis seems promising when no Gaussian normal basis exists for the field, and it can easily carry out both squaring and multiplication operations. Many squaring operations and multiplications are needed when computing the digital signatures of elliptic curve digital signature algorithm. The proposed systolic Dickson basis multiplier can concurrently compute a great number of multiplications with a high-throughput rate, thereby substantially increasing the speed of computation for digital signatures.

Gaussian normal basis multiplier over GF(2 m ) using hybrid subquadratic-and-quadratic TMVP approach for elliptic curve cryptography

In recent years, subquadratric-and-quadratric Toeplitz matrix–vector product (TMVP) computations are widely used for the implementation of binary field multiplication in elliptic curve cryptography. Pure subquadratric TMVP structure involves significantly less space complexity and long computational delay, while quadratric TMVP structure involves larger space complexity and less computation delay. To optimise the tradeoff between time and space complexities, this study presents a novel hybrid multiplier for Gaussian normal basis (GNB) in GF(2 m ) which combines subquadratic and quadratic structures. From the theoretical analysis, it is shown that the proposed hybrid multiplier can save ∼18% space complexity and 12% time complexity than the existing GNB multiplier with pure TMVP decomposition.

Problems on Gaussian Normal Basis Multiplication for Elliptic Curve Cryptosystem

Several standards such as IEEE Standard 1363-2000 and FIPS 186-2 employ Gaussian normal basis (GNB). Gaussian normal basis is a special class of normal basis. Gaussian normal basis can solve the problem that multiplication in normal basis is an very difficult and complicated operation. Two equations have been proposed in the literature to transfer GNB to polynomial basis for easy multiplication. However, we find that GNB is not correctly transformed to polynomial basis for some m values over \(GF(2^{m})\). We will show the problems and expect some feedback about this problem from other researchers.

The Study of Resonance Angle of Surface Plasma Waves in Different Air Films Thickness of Otto Configuration to Potassium Chloride

Subject of this paper is study with different air layer thickness changes to computer simulation , and find this new style Otto configuration to best air layer thickness of excitation surface plasma wave, and the entire simulation results for in-depth analysis and discussion. This paper use frustrated total internal reflection method combined with otto type configuration (gaas Prism-potassium chloride-copper metal film) (otto was the original Configuration of the basic configuration: Glass Prism-air-Metal film) to stimulate the metal surface plasma waves-the study of potassium chloride. The study configured in this study that the air layer thickness 60 (nm) when surface plasma waves produced has the best deep and narrow surface plasma wave resonance angle.

Surface Plasmon Resonance and Dielectric Core Effects on Two-Dimensional Periodic Arrays of Silver Nanospheres in a Square Lattice Embedded at Different Depths in a Silica Substrate

The dielectric core effects and surface plasmon resonance (SPR) modes of a two-dimensional (2D) periodic array of silver nanospheres (PASNSs) in a square lattice embedded at different depths in a silica substrate normally illuminated with the x-polarization plane wave are numerically investigated by using the finite element method with three-dimensional calculations. The unit cell of the 2D PASNSs examined is a unique structure, which is composed of a metallic nanoshell and a dielectric core (DC). Results show that the near-field optical properties and SPR modes obtained from the embedding cases of 2D PASNS are quite different from those of the solid cases of their counterpart, resulting in a field intensity increase and a redshift due to the plasmon hybridization of metallic nanoshells and their DCs. The strength of the hybridization depends on the geometry of the composite metallic nanoparticles and the surrounding media. On the basis of our simulations, we find two important parameters, i.e., the permittivity of the media filling DCs and the depth of the 2D PASNSs embedded in a silica substrate, which can affect the transmittance spectra and the position of SPR wavelengths. The intensity of transmittance spectra is reduced and the peak resonance is redshifted as the depth of the embedded 2D PASNSs is increased.