查看更多>>摘要：Illumination plays a very important role in observing a long-distance or dark target. Due to the limitation of the output power of single channel laser, multiple incoherent beams with combining technology can be selected as the source of illumination. In present paper, the illumination using incoherent beam combining technology has been studied. The effects of arrangement of incoherent beam combining and the atmospheric turbulence on the illumination have been simulated. Results show that the turbulence effects can be suppressed by optimizing the parameters of the beam arrays.
查看更多>>摘要：In this paper, a low-complexity approach is proposed for the generation of power efficient impulse radio ultra-wide band (IR-UWB) waveforms. The proposed approach relies on the optimization of the pulse width to achieve the highest power efficiency while maintaining FCC-compliant pulse shapes. Analytical expressions are developed for the power efficiency of widely adopted UWB waveforms, namely Gaussian and sech basis waveforms. The proposed approach is verified analytically and compared to results obtained through other approaches in the literature. It is shown that using as low as a single first order derivative Gaussian or sech basis waveform, with optimized pulse width can result in power efficiency as high as 85%, an efficiency that is achieved by other approaches using linear combinations of as much as 33 basis waveforms. This represents the low-complexity advantage of the proposed approach, which makes it more practical for implementation.
查看更多>>摘要：The time-division multiplexing (TDM) interferometric fiber optic gyroscopes (IFOGs) technology has a great significance in space applications with the pressing need for limited size, weight, and power consumption (SWP), where the parameters affecting the performance of IFOGs will inevitably face constraints. As the most important index to evaluate the noise characteristic, angular random walk (ARW) is the critical object of concern in the design of TDM IFOGs. This paper presents an ARW model based on the signal-to-noise ratio of TDM IFOG. With the model, the effects of source power, fiber length, modulation phases, and fiber loss on the ARW are analyzed and simulated. The cross-impact of multiple parameters on the ARW is also investigated. Based on the ARW model and parameters analysis, an efficient multiple-parameter optimization method is proposed to obtain the optimal design parameters, with a lower cost of SWP. Finally, the results of parameter optimization are presented in some practical cases.
查看更多>>摘要：The continuous-variable orbital angular momentum squeezed states is a crucial resource in the implementation of quantum precise measurement, super-resolution quantum imaging, and quantum storage. Currently, only the lower-order orbital angular momentum squeezed states can be generated by an optical parametric oscillator. However, the higher-order orbital angular momentum squeezed states are more useful for reliable quantum information processing. Here, we use a vortex plate to generate a series of higher-order orbital angular momentum squeezed states. The measured 20th-order orbital angular momentum squeezing is - 3.5 dB. The method may find important applications in high-dimensional quantum information processing and highcapacity quantum communication networks.
Zayed, Elsayed M. E.Gepreel, Khaled A.El-Horbaty, MahmoudYildirim, Yakup...
9页
查看更多>>摘要：This paper recovers optical solitons in birefringent fibers with the governing system that is derived from the Kaup-Newell equation. Two integration schemes are employed in this study. They are the direct algebraic and unified Riccati equation approaches. Singular, dark and bright solitons are retrieved. Jacobi elliptic and periodic solutions are also yielded. These solutions depend on certain parameter restrictions.
查看更多>>摘要：In this research Raman spectroscopy and photoluminescence (PL) spectroscopy measurements reveal different optical characteristics between monolayer (1 L) and bilayer (2 L) WS2 due to the interlayer interaction. First, ultralow frequency (ULF) Raman spectra indicate that 2 L WS2 shows additional shear mode (S) and layer-breathing (LB) mode in comparison with 1 L WS2. The 2 L WS2 has the in-plane vibration mode E12g red-shifted while the out-plane vibration mode A1g blueshifted. Then, both direct transition (DT) and indirect transition (IT) emission are observed in the PL spectra for 2 L WS2 while only DT for 1 L WS2. The PL signal corresponding to localized excitons, that is measured as a low energy side tail with the DT emission, is more prominent for 1 L WS2 at low temperature of 7 K. The DT emission and IT emission show opposite variation trend as the temperature increases from 7 K to 300 K, while the average phonon energy in 2 L WS2 is estimated to be almost twice of that for 1 L WS2. These observations illustrate that the interlayer interaction not only change the phonon characteristics for WS2, but also impact the energy band structure and the exciton dynamics, including exciton radiative recombination and excitonphonon interaction.
查看更多>>摘要：In this work, we have studied and simulated of electrical and optical properties The of InAs/InGaAs quantum dot in-a-well (DWELLs) long-wave infrared photodetector (IP). The effect of number and thickness of InAs quantum dot (QD) layers, as well as the InGaAs quantum well (QW) width on the quantum dot infrared photodetector (QDIPs) performance has been investigated. Our results have been shown that 30 quantum dots of 7 nm thickness and 6 nm well width give optimal values for responsivity, detectivity and noise equivalent power with values of 1.285 A/W, 7.66 * 10(12) cm Hz(1/2) W-1 and 10(-11) W, respectively. In addition, the wavelength ranges detected in the same structure are medium infrared (4.47 mu m), long infrared (11.47 mu m) and very long infrared (22.08 mu m) wavelength, respectively. These results confirm that InAs/InGaAs DWELL infrared photodetector performances are more sensitive to the structure geometry as well as their intrinsic parameters.
Saharia, AnkurMudgal, NiteshChoure, Kamal KishorMaddila, Ravikumar...
13页
查看更多>>摘要：All-optical processors and logic circuits are already doing wonders in the current research technologies. In connection to high-speed processors, this manuscript demonstrates a novel technique to implement an all-optical read-only memory element using an optical microring resonator. In the given article the authors have analysed the numerical modelling of Si3N4 based optical microring resonator (MRR). This silicon nitride-based MRR is modulated using an optical pumping signal which ultimately helps to achieve the optical switching through the constructed device using its nonlinear properties. The theoretical studies of the devices have been proved using simulation analysis. The obtained figures of merit like on-off ratio, extinction ratio, quality factor and finesse are very promising thus proves the practical feasibility of the proposed structure
查看更多>>摘要：Recent times have seen a massive rise in the transmission and storage of DICOM images. This work proposes a cryptosystem with the sturdy JSMP map, for the pixel data of the DICOM file. The proposed system is designed to work in the bit plane level for high resilience. To achieve an effective cryptosystem, the number of bit planes generated depends on the bits stored attribute and not on the conventional method of bits allocated of each pixel. Only the MSB bit planes that contribute more to the details of the image are shuffled with the JSMP chaotic keys. Then the shuffled image is reconstructed by combining all the MSB and LSB bit planes. Finally, a robust cipher image is generated by diffusing the reconstructed image with a random image generated with JSMP map. The novelty and uniqueness of the system lie in its capability of encrypting DICOM images with any pixel depth. The distinctive feature of this system is the unique key generation algorithm and the variable number of keys, which contributes to high sensitivity and entropy. Performance measures of the encrypted image illustrate the robustness of the cryptosystem in the health information system.
查看更多>>摘要：In this work, we study an extended (2+1)-dimensional perturbed nonlinear Schrodinger equation (P-NLS) with Kerr law nonlinearity in a nano optical fiber. The extended model includes fourth-order spatial derivatives. We study the influence of the nonlinearity and spatial dispersions effects given in spatial directions x and y. Various types of optical soliton solutions, that describe different structures of optical solutions, such as bright solitons, dark solitons, exponential, rational, and others as well, are extracted. The study is carried out by means of useful soliton ansatzes to retrieve this variety of optical soliton solutions. The obtained findings demonstrate that the implemented techniques are capable of identifying the exact solutions of other nonlinear evolution equations that arise in a range of scientific and engineering fields.
NSTL
Elsevier