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In this paper, Differential Evolution (DE) algorithm is applied to design photonic crystal fibers structure with desired properties over the C communication band. In order to determine the effective index of propagation of mode and then, the other properties of structure, Finite Difference Frequency Domain (FDFD) solver is used. The results revealed that the proposed method is a powerful tool for...
Since the introduction of side-channel attacks, cryptographic devices have been highly susceptible to power and electromagnetic analysis attacks; because these attacks require only relatively inexpensive equipments. Unless adequate countermeasures are implemented, side channel attacks allow an unauthorized person to reveal the private key of a cryptographic module. As a new countermeasure a novel...
Mode-locking and related forms of mode coupling in lasers provides important techniques for generating ultra short light pulses and other useful forms of periodically modulated lasers. On the other hand photonic crystal waveguides, provide unique properties that are not available in conventional TIR (total internal reflection) waveguides. Specially we know that in these waveguides the group velocity...
In this paper, a modified designing method about PCFs with large modal area, low confinement loss and flattened dispersion in a wide wavelength range is proposed. All air holes are arranged in the section according to triangular regulation and with identical spacing. The thirteen air holes which arranged in the snowflake shape in the middle of the section are replaced with high index inclusions that...
We present design and modeling of photonic crystal (PC) hybrid waveguides with quasi-flat transmission band. The finite-difference time-domain (FDTD) and coupled-mode theory (CMT) methods are used to simulate the PC hybrid waveguide of square lattice. The bandwidth of the hybrid waveguide is investigated for different radius of the coupled cavities. The transmission of a 200-fs pulse at 1550 nm is...
A novel octagonal photonic crystal fiber (O-PCF) with octagonal structure is proposed. The O-PCF has ultra-flattened dispersion and negligible loss characteristics throughout the third telecommunication window (1.55 mum to 1.7 mum). The design strategy to achieve these properties is based on optimization of tow air-hole diameters. The validation of the proposed design is carried out by employing a...
In today's overwhelming world of data, ultra-wideband communication systems are the inevitable parts of the communication society that has faced scientists with challenging and new problems. Appearance of nonlinear effects in optical fiber communication systems due to wideband data transmissions with the aid of ultra-short pulses has recently attracted a lot of publicity. In this paper, a thorough...
Misalignment and deviation angle in the optical interferometer directly decrease the accuracy of nanometrology system by producing a periodic nonlinearity error. In this paper, the effect of non-orthogonally polarized beams on the displacement measurement error in the advanced nanometrology system is presented. A system for reduction of non-orthogonality effect including linear polarizer, half-wave...
Entanglement purification is essential to distill highly entangled states from less entangled ones. Existing general purification protocols are based on the quantum controlled-NOT (CNOT) or similar quantum logic operations, which are very difficult to implement experimentally. Here we present a feasible scheme for the implementation of entanglement purification based on planar lightwave circuit (PLC)...
In todaypsilas world of digital communication, high capacity high performance digital data storage is an ultimate solution to preserve sheer volume of data. Nanotechnology emerges to bring new digital media with high capacity and high performance, where digital data is stored at nano-scale. In this paper a quantum dot cellular automata ROM (QDCROM) has been designed and simulated. This ROM has a very...
In this article, perfectly matched layer (PML) for the boundary treatment and an efficient compact two dimensional finite-difference time-domain (2-D FDTD) method were combined to model photonic crystal fibers (PCF). For photonic crystal fibers, if we assume that the propagation constant along the propagation direction is fixed, three-dimensional hybrid guided modes can be calculated by using only...
A new method of nonlinearity reduction for accuracy improvement in the displacement measurement system based on the heterodyne Doppler-interferometry method is presented. A two-frequency He-Ne laser at 633 nm central wavelength and 152 MHz free spectral range is used as a source. The electrical induction and unwanted electromagnetic leakage between the reference and measurement paths produce nonlinearity...
In this paper, a frequency-path model for three-longitudinal-mode interferometer (TLMI) is presented. The model describes two main error sources that affect the accuracy of displacement in heterodyne interferometers. Unwanted leakage between the reference and the target paths and inter-modulation error due to the nonlinearity of current to voltage converter, double balanced mixer, and pre-amplifier...
In this paper, an optimization approach is presented to decrease the dark current in GaAs/AlGaAs QWIPs. Dark current noise, as shown, can be reduced by increasing Al density in barriers, decreasing detector dimensions and increasing the periodic length of the structure. It is also shown that increasing the number of periods can reduce both the dark current and responsivity. Therefore, devices can...
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