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.

Haoyang Song

Feiyu Sun

Yunxu Sun

Wei Liu

The Optimization of Multimode Fiber Speckle Sensor for Microvibration

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.

Muhammad Farooq Saleem

Ghulam Abbas Ashraf

Muhammad Faisal Iqbal

Rashid Khan

Muhammad Javid

Tianwu Wang

Factors Affecting Terahertz Emission from InGaN Quantum Wells under Ultrafast Excitation

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%.

Pengcheng Liu

Wei Ji

Qiang Liu

Xuwei Xue

AI-Assisted Failure Location Platform for Optical Network

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 <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" width="27.515pt" style="vertical-align:-2.26807pt" id="M1" height="11.5564pt" version="1.1" viewBox="-0.0498162 -9.28833 27.515 11.5564"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-41" d="M300 -147C201 -63 143 98 143 270S200 602 300 686L282 710C136 610 70 450 70 271V270C70 89 136 -72 282 -170L300 -147Z"/></g><g transform="matrix(.013,0,0,-0.013,4.498,0)"><path id="g113-50" d="M384 0V27C293 34 287 42 287 114V635C232 613 172 594 109 583V559L157 557C201 555 205 550 205 499V114C205 42 199 34 109 27V0H384Z"/></g><g transform="matrix(.013,0,0,-0.013,10.738,0)"><path id="g113-55" d="M137 343C167 482 260 545 321 574C357 591 397 603 429 609L423 641C382 634 335 622 295 608C189 570 37 457 37 238C37 84 125 -12 242 -12C362 -12 447 89 447 209C447 311 374 393 267 393C247 393 226 386 204 376L137 343ZM227 337C318 337 361 256 361 173C361 105 336 22 258 22C176 22 126 120 126 240C126 266 127 291 132 310C155 323 189 337 227 337Z"/></g><g transform="matrix(.013,0,0,-0.013,19.884,0)"><path id="g117-42" d="M528 54L331 254L528 455L492 493L294 291L96 493L60 455L257 254L60 54L96 16L294 217L492 16L528 54Z"/></g></svg><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" width="17.234pt" style="vertical-align:-2.26807pt" height="11.5564pt" version="1.1" viewBox="30.370183800000003 -9.28833 17.234 11.5564"><g transform="matrix(.013,0,0,-0.013,30.42,0)"><path id="g113-51" d="M412 140C382 77 369 73 315 73H129L270 222C362 320 402 379 402 466C402 571 322 635 234 635C177 635 130 609 99 576L42 495L64 475C90 514 133 568 201 568C274 568 318 519 318 435C318 349 255 267 193 193C144 135 87 78 32 23V0H405C417 45 427 89 440 131L412 140Z"/></g><g transform="matrix(.013,0,0,-0.013,36.66,0)"><use xlink:href="#g113-51"/></g><g transform="matrix(.013,0,0,-0.013,42.9,0)"><path id="g113-42" d="M275 270C275 450 212 609 64 710L45 686C145 604 203 442 203 270S147 -63 45 -147L64 -170C213 -68 275 89 275 270Z"/></g></svg>. 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.

Meshari Alsharari

Khaled Aliqab

Farman Ali

Ammar Armghan

Integrated Free-Space Optics and Fiber Optic Network Performance Enhancement for Sustaining 5G High Capacity Communications

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%.

Parinaz Khaledi

Mahdi Behboudnia

Mohammad Karimi

Optimization and Numerical Modeling of TCO/SnO2/CdS/CdTe Solar Cells

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.

Qiang Xu

Yunhua Cao

Yuanyuan Zhang

Shaohui Yan

Yiping Han

Zhensen Wu

The Multiple Scattering of Laser Beam Propagation in Advection Fog and Radiation Fog

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International Journal of Optics publishes both fundamental and highly applied studies on the nature of light, its properties and behaviours, and its interaction with matter.

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Chief Editor, Professor Cerullo, leads the Ultrafast Spectroscopy group at the Department of Physics at the Polytechnic University of Milan. His research activity has mainly focused on the physics and applications of ultrashort pulse lasers.

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International Journal of Optics - Table of contents 2023

International Journal of Optics | Hindawi

title

International Journal of Optics publishes both fundamental and highly applied studies on the nature of light, its properties and behaviours, and its interaction with matter.

International Journal of Optics