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International Journal of Optics
Number of Followers: 15

This is an Open Access Journal

Open Access journal
ISSN (Print) 1687-9384 - ISSN (Online) 1687-9392
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Dual Optical Injection in Semiconductor Lasers with Zero Henry Factor
- Abstract: The dynamics of semiconductor lasers subject to dual optical injections are numerically investigated with a zero linewidth enhancement factor. With the aid of stability maps, we show that different chaotic and nonlinear dynamics can be produced (even with zero linewidth enhancement factor) by injecting an additional optical signal. We also study the bifurcation of the system and the carrier dynamics under dual optical injection and a zero linewidth enhancement factor.
  PubDate: Tue, 07 May 2024 13:35:00 +000
Study on the Terahertz Spectroscopy Properties of Graphene Quantum Dots
Based on Microfluidic Chip
- Abstract: Graphene quantum dots are quasi-zero-dimensional nanomaterials with unique physical and chemical properties. This study utilized a terahertz (THz) time-domain spectroscopy system to analyze the absorption characteristics of THz-waves by graphene quantum dots at different concentrations. Additionally, we applied electric fields and magnetic field to explore the THz-wave absorption properties of graphene quantum dots in greater detail. The results indicate that the THz absorbance of graphene quantum dots is positively correlated with sample concentration and applied electric field strength. However, it is negatively correlated with the intensity of the applied magnetic field. This work combines THz technology and microfluidic devices to propose a viable methodology for conducting in-depth study on graphene quantum dots.
  PubDate: Mon, 29 Apr 2024 11:20:01 +000
Advancements in Synthesis Strategies and Optoelectronic Applications of
Bio-Based Photosensitive Polyimides
- Abstract: With the rapid development of information, energy, and materials industries in China, the demand for high-performance polymers is gradually increasing. Photosensitive polyimide (PSPI) has emerged as an ideal choice for high-performance optoelectronic materials due to its outstanding thermal stability, mechanical strength, and low dielectric constant. In particular, bio-based photosensitive polyimide prepared from bio-based chemicals, as a green polymer material, not only reflects the advantages of environmental protection and resource efficiency but also contributes to carbon neutrality. However, how to improve the photolithography efficiency while maintaining the thermodynamic performance and environmental friendliness and how to balance the pros and cons of low-molecular-weight matrixes are still challenges in the research. This review systematically summarizes the synthesis and performance characteristics of photosensitive polyimides, bio-based polyimide, and bio-based photosensitive polyimides and further explores the future application prospects of bio-based polyimides in the field of high-performance optoelectronic materials.
  PubDate: Fri, 01 Mar 2024 14:05:01 +000
Temperature-Dependent Electromagnetic Surface Wave Supported by
Graphene-Loaded Indium Antimonide Planar Structure
- Abstract: In this study, the propagation characteristics of EM surface waves supported by the graphene-coated indium antimonide (InSb) planar waveguide have been investigated theoretically and numerically. The modeling of graphene has been performed by use of Kubo formalism whereas the relative permittivity of indium antimonide has been calculated using Drude’s model. The results for transverse electric (TE) and transverse magnetic (TM) polarized surface waves have been computed analytically and numerically. The major challenge is to model the atomically thick graphene sheet over the InSb grounded slab. To get the temperature-dependent characteristic equation for the electromagnetic surface waves, the surface current boundary conditions’ approach has been employed. The numerical results have been computed for both the TE and TM polarization states and reported that the TE does not support the propagation of surface waves. The dispersion relation, effective mode index, phase speed, propagation length, and field profile have been computed in Mathematica under TM polarization. The graphene and indium antimonide have been found active for low and high Terahertz regions, respectively. As temperature increases, the plasma frequency of the InSb increases due to this reason with the increase of temperature and the resonance frequency, leading to a shift in the dispersion curve. Moreover, with the increase of temperature, the effective wave number of transverse magnetic polarized surface waves also increases. Resultantly, the confinement of such surface waves supported by graphene-loaded InSb increases. It is shown that with the variation of temperature of indium antimonide, the surface waves propagating across the interface can be tuned in the Terahertz region and can be exploited for thermo-optical sensing, near-field communications waveguides, and graphene-based temperature sensor designing.
  PubDate: Fri, 05 Jan 2024 12:20:00 +000
The Propagation Properties of a Lorentz–Gauss Vortex Beam in a
Gradient-Index Medium
- Abstract: Based on the Huygens–Fresnel integral and ABCD matrix, the propagation equation for the Lorentz–Gauss vortex beam (LGVB) in a gradient-index medium (GRIN) is rederived. The evolution of the intensity and phase distributions of an LGVB through a GRIN medium are numerically calculated as a function of the gradient-index parameter with changes in the incident beam parameters. The results showed that the propagation path and intensity distributions changed periodically with increasing propagation distance. In contrast, phase distributions change at multiples of or , depending on whether the values are odd or even, respectively. At the same time, the parameters of the gradient index determine the periodic values of the Lorentz–Gauss vortex beams during propagation, and as increased, the period of evolution decreased. The Lorentz–Gauss vortex beam propagating through the gradient index will develop from a square beam to a Gaussian vortex beam more quickly with an increase of . In addition, the topological charge affects the size of the dark spot at the center of the beam and the size of the beam, causing the phase distributions to change periodically in the medium. This study is beneficial for laser optics and optical communications.
  PubDate: Thu, 28 Dec 2023 10:35:01 +000
Effect of the Dispersion Orders on the Widths of the Coexistence Domain
and Combs Spectra of Bright and Dark Solitons in Microresonators
- Abstract: Using the Lugiato–Lefever model, we base on the hysteresis approach to analyze the coexistence domain of bright and dark solitons in the zero, normal, and anomalous dispersion regimes. Our results also highlight that the fourth-order dispersion term affects the width of the frequency combs of both dark and bright solitons. It also allows the appearance of dispersive waves on the soliton spectra that disappear for high values of the fourth-order dispersion followed by the soliton destabilization into harmonic oscillations and oscillation packages.
  PubDate: Fri, 08 Dec 2023 11:50:01 +000
Design of Ultrasmall Plasmonic Logic Gates Based on Single Nanoring
Dielectric-Metal-Dielectric Waveguide
- Abstract: This paper proposes a new configuration of dielectric-metal-dielectric (DMD) waveguides to design optical logic gates. Seven plasmonic logic gates, including NOT, OR, AND, NAND, NOR, XOR, and XNOR, are realized by one nanoring and four DMD plasmonic waveguides. To realize the logic gates, an ultrasmall size of 300 nm × 300 nm device is designed. The performance of the plasmonic logic gates is based on constructive and deconstructive interference between input and control ports. To evaluate the logic state of the output port, the threshold transmission limit is assumed to be 0.35. The transmission ratio, T, contrast ratio, CR, modulation depth, MD, insertion loss, IL, and contrast loss, CL, parameters measure the seven logic gates’ performance. A maximum T of 232% is obtained for AND, OR, and XNOR logic gates. Simulation results show that the dimensional parameters are optimized because of very high MD for all seven logic gates. Maximum values of CR and CL are obtained for the NOT gate. For the AND gate, a minimum IL value is achieved. The studied plasmonic logic gates can be employed in building blocks of all-optical signal-processing nanocircuits and nanophotonics devices. The finite element method (FEM) simulates the structure with COMSOL Multiphysics 5.4 software.
  PubDate: Tue, 21 Nov 2023 10:05:01 +000
Effect of Co-Doping on the Photoelectric Properties of the Novel
Two-Dimensional Material Borophene
- Abstract: Borophene is a novel two-dimensional material with abundant crystal structure and photoelectric properties. We focus on the effect of co-doping on the electronic structure and optical properties of borophene using the first-principles method. The results show that the structure of Al and Ga co-doped borophene is obviously distorted because Al and Ga atoms have formed bonds with a bond length of 2.378 Å, and the two B atoms that bond together with Al and Ga are no longer formed bonds. However, it is also a two-dimensional planar structure after co-doping. After co-doping, the band gap width of the borophene system is narrowed from 1.409 eV to 1.376 eV, and the band gap is narrowed by 0.033 eV. Mulliken population analysis shows an obvious charge transfer between Al-B and Ga-B atoms in the co-doped borophene. The calculation of optical properties shows that the static dielectric constant ε1 (0) increases from 5.08 to 7.01, and ε2 (ω) is larger than that of the undoped sample in the low-energy range. Thus, the co-doping of Al and Ga can enhance the electromagnetic energy storage capacity and the visible light absorption ability. Although the reflectance of borophene is reduced by co-doping (the peak of the reflectivity can be decreased from 71% to 61% at E = 2.94 eV), it still presents metallic reflection characteristics. The static refractive index n0 can be increased from 2.25 to 2.65 by co-doping. The extinction coefficient shows strong band edge absorption at the low-energy range with an absorption edge of 0.85 eV. The light loss is limited to a very narrow energy range of approximately 7.30 eV, which indicates that borophene co-doped with Al and Ga can also be used as a light storage material. The optical conductivity reaches its maximum at E = 1.78 eV and 2.52 eV, which correspond to the light irradiation with a wavelength of 698 nm (red light) and 492 nm (cyan light), respectively. The results show that the Al-Ga co-doped borophene is sensitive to cyan light and red light, so it can be used to make photosensitive devices. The results can hopefully fill the gap in the application of borophene in semiconductor photoelectric devices and provide a theoretical basis for its application.
  PubDate: Mon, 06 Nov 2023 15:05:01 +000
Refractometric Sensing of Protein in Urine by the Photonic Crystal Fiber
Biosensor in THz Regime
- Abstract: The presence of albumin in human urine is one of the confirmed early symptoms of kidney dysfunction. A precise urine protein identification process is very important to monitor the kidney’s proper functioning. To identify the presence of albumin in urine, a refractometric protein sensing approach in the photonic crystal fiber (PCF) environment has been introduced here. A PCF geometry with suspended cladding and a circular hollow core has been proposed and investigated in the terahertz (THz) spectrum for protein identification in the liquid samples. Three levels of albumin concentrations in urine (7–125 mg/dl, 250–500 mg/dl, and 1000 mg/dl) are considered to evaluate the sensing performances of the proposed PCF. The numerical investigations are performed on the COMSOL Multiphysics platform where the finite element method (FEM) figures out the numerical outcomes. The performances of the proposed PCF exhibit highly sensitive characteristics for albumin identification in the different albumin concentration levels of urine. The sensitivity shows more than 98.5% for all the tested concentration levels due to the strategic selection of geometrical parameters and proper optimization. Alongside, negligible confinement loss of 10−16 cm−1 is attained at the same operating point of 4.3 THz. Furthermore, dispersion profiles and practical implementation strategies are also investigated and discussed in detail.
  PubDate: Thu, 26 Oct 2023 12:20:01 +000
Fast Backprojection Filtration Algorithm in Circular Cone-Beam Computed
Tomography
- Abstract: In order to meet the heavy backprojection calculation of the backprojection filtration (BPF) algorithm in circular cone-beam computed tomography (CT), a fast backprojection method is developed, which uses the integral operator of the fixed scanning angle integral interval. The proposed method combines with Hilbert filtration and the filter of the Blackman window, and then, the fast BPF (F-BPF) algorithm is obtained. The experimental results of simulation data and real data demonstrate that the proposed algorithm is fast enough for high-quality reconstructed images only with half-circle projection data.
  PubDate: Mon, 23 Oct 2023 11:05:01 +000
Classical and Quantum Surface Plasmon Resonance Biosensing
- Abstract: Surface plasmon resonance is an optical phenomenon first discovered in 1902. The phenomenon has since had many applications, particularly in biosensing. In this paper, we review surface plasmon resonance-based biosensing, look at recent progress made in integrating quantum resources to develop surface plasmon resonance-based biosensors into a class of surface plasmon resonance biosensors commonly referred to as quantum surface plasmon resonance biosensors, and examine the advantages which quantum biosensors bring. We will review recent experimental and theoretical work showing that making use of quantum states of light offers a great enhancement in the precision of our biosensor, as they can go below the shot-noise limit (standard quantum limit) of precision in intensity noise detection. An overview of the surface plasmon resonance mechanism, its applications, and some limitations, as well as a report on recent research to address certain limitations and quantum-based surface plasmon resonance sensing, are provided.
  PubDate: Wed, 18 Oct 2023 13:05:01 +000
3D Reconstruction and Measurement Analysis of a Dense Point Cloud Fused
with a Depth Image
- Abstract: To solve the problems of holes, noise, and texture information missing in the traditional incremental reconstruction of complex surface objects, a 3D reconstruction method of depth image fusion surface dense point clouds is proposed, and texture feature creation is combined to obtain a 3D reconstruction model that takes into account the main body and details of the reconstructed object. First, the mechanism of surface dense reconstruction based on the patch-based multiview stereo (PMVS) algorithm is analyzed. Combined with the principle of view angle selection of stereo images, surface point cloud density reconstruction is performed. Then, the depth value is optimized by the region growing method, and the optimization model is established. The depth image is fused into a dense surface, and the reconstructed part is supplemented by the depth information. Finally, the Markov random field (MRF) is introduced to describe the richness of image details, and combined with the calculating method of the area coordinate, the texture coordinates are accurately calculated to reproduce the texture details of the 3D reconstruction model. 3D reconstruction experiments are performed on multiple indoor and outdoor model surfaces, and the experimental results show that the proposed method can achieve complete and accurate reconstruction of complex surface objects. Our method provides technical support for complex surface topography detection and has industrial practical significance.
  PubDate: Fri, 08 Sep 2023 06:50:01 +000
Design and Analysis of Target Simulator Using All Spherical System with
High Matching Rate
- Abstract: To achieve low wavefront error and high throughput with vignetting-free target simulators, a concave-convex-concaveoff-axis spherical system is designed in this paper, which effectively eliminates astigmatism and coma of the system by fields of view (FOVs) and aperture offset and provides theoretical basis for the realization of 100% matching between the exit pupil of the field lens and entrance pupil of the three-mirror anastigmat (TMA) system. Only spherical mirror element is used in this target simulator, which not only reduces the difficulty of manufacturing and cost but also greatly reduces the difficulty of assembling and adjusting. It provides an effective scheme for the design of target simulator and has strong engineering application value.
  PubDate: Fri, 08 Sep 2023 06:35:00 +000
One-Point and Multiline Calibration Fiber-Optic Laser-Ablation
Spark-Induced Breakdown Spectroscopy for Quantitative Analysis of Elements
in Aluminum Alloys
- Abstract: Rapid and accurate analysis of element concentrations in aluminum alloys is crucial due to their widespread use in modern industry. This paper proposes a one-point and multiline calibration fiber-optic laser-ablation spark-induced breakdown spectroscopy (OP-MLC FO-LA-SIBS) for the quantitative analysis of elements in aluminum alloys. The experimental system utilizes a compact fiber laser as the laser-ablation source and spark discharge to enhance the atomic emission. A portable multichannel fiber spectrometer is used to quickly collect spectra in the nongated mode. The concentrations of four elements (Mg, Cr, Cu, and Mn) in four aluminum alloy samples were calculated using the simple and efficient OP-MLC method, which involves taking another sample with a similar matrix as the standard sample. The average relative errors (AREs) for Mg, Cr, Cu, and Mn were 6.38%, 28.09%, 21.92%, and 18.97%, respectively. When the certified concentrations are greater than 0.02 wt.%, the ARE is only 13.04%. The OP-MLC FO-LA-SIBS system is compact, features simple spectra processing, and offers effective measurement, providing a convenient method for rapid and efficient quantitative analysis of elements in aluminum alloys in industrial production.
  PubDate: Mon, 17 Jul 2023 12:50:01 +000
Solar Light Radiometry Calibration Unit for a ScanPol Polarimeter of the
Aerosol-UA Space Mission
- Abstract: The Aerosol-UA space mission will study aerosol microphysical characteristics in the Earth’s atmosphere based on the multispectral scanning polarimeter (ScanPol) and imaging polarimeter (MSIP). Both polarimeters must be precisely calibrated on the ground and in orbit to provide correct measurements. This paper considers the results of developing an experimental device for the radiometric calibration of the ScanPol. We consider the calibration unit design and operation principle to form a luminous flux with unchanged or well-predicted characteristics in a specified direction. The construction of the radiometric calibration unit is based on a sun-illuminated reflective diffuser made from the white opal glass MS20. We evaluated the scattering and polarization characteristics of the diffuser in laboratory experiments at a wide range of wavelengths. The results suggest that the polarization properties of the diffuser are negligible. The diffuser scattering parameters are close to Lambertian for illuminance conditions, which is necessary for radiometric calibration. The calibration unit was manufactured and tested during field observations of solar radiation. The results will be used for its improvement, mainly to reduce the observed stray scattered radiation entering the telescopes of the ScanPol polarization state analyzer.
  PubDate: Mon, 10 Jul 2023 11:50:00 +000
A MIMO-Enabled Free Space Optical Link under Log-Normal Fading/Gamma-Gamma
Channel: Exploring an Optimal Modulation Scheme
- Abstract: The technology of free-space optical communication (FSOC) systems has some distinctive merits compared to other technologies. Its use is extremely beneficial to meet the exigencies of optical telecommunications and wireless networks (OTWNs). However, since the OTWNs transport a lot of data, the choice of a reliable modulation scheme is highly crucial. To this end, the focus of this paper is an in-depth study of a Point-to-Point Optical Link (P2P-OL) system under a FSOC-Multiple-Input Multiple-Output (MIMO) channel using an optimal modulation scheme. Furthermore, atmospheric turbulence (AT) effects over the FSOC-MIMO channel are incorporated in the proposed system to obtain substantial results. The performance analysis test of the proposed high-rate P2P-OL system is validated under the case that the channel decreases significantly when the AT gets strong regimes. Finally, the proposed system uses an optimal Non-Return to Zero Pulse Generator-Mach-Zehnder Modulator ((NRZPG-MZM)) scheme, which displays acceptable performance levels in a dust-fog meteorological environment under a LNF FSOC-9 × 9 channel with the attenuation value of 59.66 dB/km (i.e., max OSNR = 24.9 dB, min BER = 1e − 09, and max Q-factor = 6), whereas with the same environment under a G-G FSOC-9 × 9 channel, the attenuation value is 58.55 dB/km (i.e., max OSNR = 24.67 dB, min BER = 1e − 09, and max Q-factor = 6).
  PubDate: Wed, 17 May 2023 15:05:01 +000
A Feasibility Study on Monitoring Shelf Life of Bottled Natural Fruit
Juice Using Laser-Induced Autofluorescence
- Abstract: Shelf life of bottled natural fruit juice (BNFJ) provides relevant information on quality and authenticity for consumer protection. However, existing techniques for monitoring the shelf life of BNFJ are destructive and time-consuming. We report on using laser-induced autofluorescence (LIAF) spectroscopic technique in combination with multivariate analysis for shelf life monitoring of BNFJ. The LIAF spectra data were acquired for nine (9) continuous days on three batches of BNFJ samples purchased from a certified retailer. Deconvolution of the LIAF spectra revealed underlying peaks representing constituents of the BNFJ. Principal component analysis (PCA) was able to monitor the trend in the changes of the BNFJ as it aged. Partial least square regression (PLSR) predicted the exact day from the production of the BNFJ accurately at 96.6% and 98.8% in the training and testing sets, respectively. We, therefore, propose the LIAF combined with multivariate analysis as a potential tool for nondestructive, rapid, and relatively inexpensive monitoring of the shelf life of BNFJ.
  PubDate: Sat, 29 Apr 2023 01:20:01 +000
Design and Theoretical Analysis of Highly Negative Dispersion-Compensating
Photonic Crystal Fibers with Multiple Zero-Dispersion Wavelengths
- Abstract: This paper presents a highly negative dispersion-compensating photonic crystal fiber (DC-PCF) with multiple zero dispersion wavelengths (ZDWs) within the telecommunication bands. The multiple ZDWs of the PCF may lead to high spectral densities than those of other PCFs with few ZDWs. The full-vectorial finite element method with a perfectly matched layer (PML) is used to investigate the optical properties of the PCFs. The numerical analysis shows that the proposed PCF, i.e., PCF (b), exhibits multiple ZDWS and also achieves a high negative chromatic dispersion of −15089.0 ps/nm·km at 1.55 wavelength, with the multiple ZDWs occurring within the range from 0.8 to 2.0 range. Other optical properties such as the confinement loss of 0.059 dB/km, the birefringence of , the nonlinearity of 18.92 , and a normalized frequency of 2.633 was also achieved at 1.55 wavelength. These characteristics make the PCF suitable for high-speed, long-distance optical communication systems, optical sensing, soliton pulse transmission, and polarization-maintaining applications.
  PubDate: Wed, 22 Mar 2023 15:05:01 +000
Research on the Seed Respiration CO2 Detection System Based on TDLAS
Technology
- Abstract: The traditional detection method of CO2 concentration in seed respiration has defects such as low detection accuracy, low detection efficiency, and inability to monitor in real time. In order to solve these problems, we report a seed respiration CO2 detection system based on wavelength modulation spectroscopy (WMS) techniques in tunable diode laser absorption spectroscopy (TDLAS). This system uses a 2004 nm distributed feedback (DFB) laser as the light source, and a double-layer seed respiration device (about 1.5 L) is designed based on Herriott cell with an effective optical path of about 21 meters. Then, the second harmonic (2f) signal is extracted by the wavelength modulation method for CO2 concentration inversion. When the ambient temperature and pressure changes greatly, the corrected 2f signal is used for CO2 concentration inversion to improve the accuracy. A series of verification and comparison experiments have proved that the seed respiration CO2 detection system has the advantages of strong stability, high sampling frequency, and high detection accuracy. Finally, we used the developed system to measure the respiration intensity and respiration rate of 1 g corn seeds. The respiration intensity curves and respiration rate change details show that the seed respiration CO2 detection system is more suitable for a small amount of seeds than nondispersive infrared (NDIR) CO2 sensor and gas chromatography in real-time monitoring of the breathing process.
  PubDate: Wed, 22 Mar 2023 15:05:01 +000
Frequency Scanning Multibeamforming Method Based on CFBG Photonic
Microwave Oscillation
- Abstract: In this paper, a two-loop photoelectric oscillator based on chirped fiber Bragg grating (CFBG) is used to construct a swept source, which acts on the frequency scanning array antenna to realise multibeamforming. The simulation results of the designed beamforming system have shown that it can realise wide-range beam scanning and has ultralow phase noise.
  PubDate: Tue, 21 Mar 2023 15:05:01 +000
The Optimization of Multimode Fiber Speckle Sensor for Microvibration
- Abstract: A vibration sensing system with optical fiber speckles is demonstrated and optimized with different optical fiber diameters and speckle statistical algorithms. The types of fiber diameter and material lead to a different performance of fiber specklegram sensor (FSS), which has been experimentally explored. The signal intensity, demodulated from the speckles, is different when using multimode fibers with different diameters. At the same time, the sensing effect of different fibers depends on the speckle statistical algorithms. Accordingly, we use different statistical methods in theory and experiment to analyze the influence of fiber diameter and speckle statistical methods on the sensing performance. A vibration sensing system with optimized performance is achieved by the optimized types of optical fiber and the corresponding optimized algorithms, which are promising for sensing weak vibration, such as detecting.
  PubDate: Fri, 17 Feb 2023 06:05:01 +000
Factors Affecting Terahertz Emission from InGaN Quantum Wells under
Ultrafast Excitation
- Abstract: InGaN quantum wells (QWs) grown on c-plane sapphire substrate experience strain due to the lattice mismatch. The strain generates a strong piezoelectric field in QWs that contributes to THz emission under ultrafast excitation. Physical parameters such as QW width, period number, and Indium concentration can affect the strength of the piezoelectric field and result in THz emission. Experimental parameters such as pump fluence, laser energy, excitation power, pump polarization angle, and incident angle can be tuned to further optimize the THz emission. This review summarizes the effects of physical and experimental parameters of THz emission on InGaN QWs. Comparison and relationship between photoluminescence properties and THz emission in QWs are given, which further explains the origin of THz emission in InGaN QWs.
  PubDate: Mon, 06 Feb 2023 15:20:01 +000
AI-Assisted Failure Location Platform for Optical Network
- Abstract: In the paper, we applied the customized AI module to the OTDR device and, combined with the optical power monitoring module, realized the AI-assisted optical network fault location mechanism for the high-density interconnection scenario of data centers. The mechanism can make full use of the data from optical links. Based on the link data, the AI module can predict the links that may fail, and then the target links will be monitored by the optical power module. The mechanism can quickly locate and respond to faulty links. Through the test, the introduction of an AI model can improve the average fault detection efficiency of the link by 98.41%.
  PubDate: Wed, 01 Feb 2023 03:20:00 +000
Integrated Free-Space Optics and Fiber Optic Network Performance
Enhancement for Sustaining 5G High Capacity Communications
- Abstract: In this paper, the integrated free-space optics (FSO) and fiber optic model is evaluated using new radio (NR) sub-THz link to sustain next generation 5G capacity. The proposed integrated model effectively applies over 25 km single mode fiber, 0.5 m RF wireless, and 500 m optical wireless. In addition, four different sub-THz frequencies (125, 150, 175, and 200 GHz) are estimated on NR-based 5G FSO network, including 22 Gbps 64quadrature amplitude modulation-orthogonal frequency division multiplexing (64QAM-OFDM) signal speed. The proposed FSO enabled fiber optic system is also measured mathematically to satisfy the data transmission accuracy. For confirmation, the theoretical approach of the presented FSO and fiber optic network is realized with an aggregate 342 Gbps speed . The performance metrics comprising forward error limit (FEL), bit error rate (BER), and error vector magnitude (EVM) are used for weighing simulation results. The outlets of an integrated fiber-FSO network show that by applying NR 5G sub-THz, a high data rate with multiple inputs and multiple outputs (MIMO) transmission capacity can be adjusted victoriously.
  PubDate: Fri, 13 Jan 2023 01:35:01 +000
Optimization and Numerical Modeling of TCO/SnO2/CdS/CdTe Solar Cells
- Abstract: Due to the excellent performance of the CdTe solar cells, research is ongoing to increase the efficiency of these cells. The first purpose of this study is to increase the accuracy of the physical parameters of a solar cell in the electron ̶hole production rate equation. In previous studies, this section was neglected because of using only ready-made software. Simulations were performed using a one-dimensional diffusion model in MATLAB and Maple software. Then, in theory, we simulated cadmium telluride-based layered solar cells for the first time without using ready-made software and with coding in MATLAB and Maple software. We designed and optimized the thickness of the layers in solar cells in detail. Then we studied the effect of layer thickness on the short-circuit current (Jsc), open-circuit voltage (Voc), filling factor (FF), and its efficiency. It is found that the efficiency of solar cells layered with TCO/SnO2/CdS/CdTe layers is as follows: the thickness of the TCO layer is 0.1 μm, that of the SnO2 layer is equal to 0.1 μm, that of the CdS layer as the window layer is 0.1 μm and the thickness of the CdTe layer as the absorber layer is 3.9 μm. The efficiency of the solar cell with the TCO/SnO2/CdS/CdTe structure increases significantly and reaches a maximum value of more than 20%.
  PubDate: Thu, 12 Jan 2023 08:50:01 +000
The Multiple Scattering of Laser Beam Propagation in Advection Fog and
Radiation Fog
- Abstract: The laser beams were scattered and attenuated when they propagate in fogs for laser communication, laser remote sensing detection. For different density and droplets distribution of fogs, the laser scatter and attenuation are different, the correspond mechanism need thorough investigation. The characteristics of laser beam scattering in different types of fogs are studied based on the droplet size characteristics of advection fog and radiation fog, the scattering coefficients of droplets with different laser wavelengths(0.86 μm, 0.91 μm, 1.06 μm, 1.3015, and 10.6 μm) are calculated, the multi scattering of laser beam is studied by the Monte Carlo method, the propagation path and scattering direction of photons is analyzed, relations between asymmetry factor, albedo of fog droplets, and the visibility are presented, and the forward scattering intensity and the backward scattering intensity versus scattering angle are gotten and discussed.
  PubDate: Tue, 10 Jan 2023 09:05:01 +000

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