Subjects -> PHYSICS (Total: 857 journals)
    - ELECTRICITY AND MAGNETISM (10 journals)
    - MECHANICS (22 journals)
    - NUCLEAR PHYSICS (53 journals)
    - OPTICS (92 journals)
    - PHYSICS (625 journals)
    - SOUND (25 journals)
    - THERMODYNAMICS (30 journals)

OPTICS (92 journals)

Showing 1 - 89 of 89 Journals sorted alphabetically
ACS Photonics     Hybrid Journal   (Followers: 16)
Advanced Optical Materials     Hybrid Journal   (Followers: 11)
Advanced Photonics     Open Access   (Followers: 3)
Advanced Photonics Research     Open Access   (Followers: 2)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 24)
Advances in Nonlinear Optics     Open Access   (Followers: 10)
Advances in Optical Technologies     Open Access   (Followers: 3)
Advances in Optics     Open Access   (Followers: 12)
Advances in Optics and Photonics     Full-text available via subscription   (Followers: 18)
Annual Review of Vision Science     Full-text available via subscription   (Followers: 4)
Applied Optics     Hybrid Journal   (Followers: 48)
Applied Physics B: Lasers and Optics     Hybrid Journal   (Followers: 35)
Atmospheric and Oceanic Optics     Hybrid Journal   (Followers: 8)
Biomedical Optics Express     Open Access   (Followers: 6)
Biomedical Photonics     Open Access  
Chinese Optics Letters     Full-text available via subscription   (Followers: 9)
EPJ Photovoltaics     Open Access   (Followers: 2)
European Journal of Hybrid Imaging     Open Access  
Fiber and Integrated Optics     Hybrid Journal   (Followers: 22)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 3)
High Power Laser Science and Engineering     Open Access   (Followers: 4)
Hindsight : The Journal of Optometry History     Open Access   (Followers: 1)
IEEE Photonics Journal     Open Access   (Followers: 17)
IEEE Photonics Technology Letters     Hybrid Journal   (Followers: 14)
International Journal of Optics     Open Access   (Followers: 14)
International Journal of Optics and Applications     Open Access   (Followers: 7)
International Journal of Optoelectronic Engineering     Open Access   (Followers: 1)
International Journal of Spectroscopy     Open Access   (Followers: 6)
International Journal of Sustainable Lighting     Open Access  
Journal of Astronomical Telescopes, Instruments, and Systems     Hybrid Journal   (Followers: 6)
Journal of Atomic, Molecular, and Optical Physics     Open Access   (Followers: 13)
Journal of Biomedical Photonics & Engineering     Open Access  
Journal of Laser Applications     Full-text available via subscription   (Followers: 14)
Journal of Mass Spectrometry and Advances in the Clinical Lab     Open Access  
Journal of Modern Optics     Hybrid Journal   (Followers: 12)
Journal of Nanoelectronics and Optoelectronics     Full-text available via subscription   (Followers: 1)
Journal of Nonlinear Optical Physics & Materials     Hybrid Journal   (Followers: 2)
Journal of Optical Microsystem     Hybrid Journal   (Followers: 1)
Journal of Optical Technology     Full-text available via subscription   (Followers: 4)
Journal of Optics     Hybrid Journal   (Followers: 14)
Journal of Optics Applications     Open Access   (Followers: 14)
Journal of Optoelectronics Engineering     Open Access   (Followers: 5)
Journal of Photonics     Open Access   (Followers: 5)
Journal of Photonics for Energy     Hybrid Journal   (Followers: 2)
Journal of Physics B: Atomic, Molecular and Optical Physics     Hybrid Journal   (Followers: 32)
Journal of the Optical Society of America A     Hybrid Journal   (Followers: 11)
Journal of the Optical Society of America B     Hybrid Journal   (Followers: 12)
Journal of the Optical Society of Korea     Open Access   (Followers: 2)
Laser & Photonics Reviews     Hybrid Journal   (Followers: 5)
Laser Physics     Hybrid Journal   (Followers: 2)
Lasers in Medical Science     Hybrid Journal   (Followers: 2)
LEUKOS : The Journal of the Illuminating Engineering Society     Hybrid Journal  
Materials Today Electronics     Open Access   (Followers: 2)
Microwave and Optical Technology Letters     Hybrid Journal   (Followers: 11)
Nature Photonics     Full-text available via subscription   (Followers: 37)
Ophthalmic and Physiological Optics     Hybrid Journal   (Followers: 3)
Optica     Open Access   (Followers: 6)
Optical and Quantum Electronics     Hybrid Journal   (Followers: 3)
Optical Engineering     Hybrid Journal   (Followers: 22)
Optical Fiber Technology     Hybrid Journal   (Followers: 10)
Optical Materials     Hybrid Journal   (Followers: 11)
Optical Materials : X     Open Access  
Optical Materials Express     Open Access   (Followers: 7)
Optical Memory and Neural Networks     Hybrid Journal   (Followers: 2)
Optical Nanoscopy     Open Access   (Followers: 1)
Optical Review     Hybrid Journal   (Followers: 2)
Optics & Laser Technology     Hybrid Journal   (Followers: 27)
Optics and Lasers in Engineering     Hybrid Journal   (Followers: 38)
Optics and Photonics Journal     Open Access   (Followers: 18)
Optics and Photonics Letters     Open Access   (Followers: 11)
Optics and Photonics News     Partially Free   (Followers: 7)
Optics and Spectroscopy     Hybrid Journal   (Followers: 8)
Optics Communications     Hybrid Journal   (Followers: 17)
Optics Express     Open Access   (Followers: 23)
Optics Letters     Hybrid Journal   (Followers: 19)
Optik     Hybrid Journal   (Followers: 9)
Optik & Photonik     Open Access  
Optoelectronics Letters     Hybrid Journal   (Followers: 1)
Photonic Sensors     Open Access   (Followers: 7)
Photonics     Open Access   (Followers: 4)
Photonics Letters of Poland     Open Access  
Photonics Research     Open Access   (Followers: 2)
PhotonicsViews     Hybrid Journal  
Progress in Optics     Full-text available via subscription   (Followers: 6)
Results in Optics     Open Access   (Followers: 3)
SIAM Journal on Imaging Sciences     Hybrid Journal   (Followers: 7)
Thin Solid Films     Hybrid Journal   (Followers: 11)
Trends in Opto-Electro & Optical Communications     Full-text available via subscription   (Followers: 1)
Virtual Journal for Biomedical Optics     Hybrid Journal   (Followers: 1)
Similar Journals
Journal Cover
IEEE Photonics Journal
Journal Prestige (SJR): 0.893
Citation Impact (citeScore): 3
Number of Followers: 17  

  This is an Open Access Journal Open Access journal
ISSN (Print) 1943-0655
Published by IEEE Homepage  [228 journals]
  • Enhancement of Optical Spin-Orbit Coupling in Anisotropic ENZ
           Metamaterials

    • Authors: Vittorio Aita;Anatoly V. Zayats;
      Pages: 1 - 8
      Abstract: Vector vortex beams which possess complex intensity and polarisation patterns, and phase or polarisation singularities are important in a variety of applications ranging from high resolution imaging and data transmission to nonlinear optics and quantum technologies. Here, we theoretically analyse the effect of vector vortex beams propagation through strongly anisotropic metamaterials exhibiting epsilon-near-zero behaviour. The interaction of the metamaterial with longitudinal field of the vector beams results in a strong modification of the polarisation distribution, with the metamaterial acting as an azimuthal polariser. The dependence on the local ellipticity of the field is also investigated revealing conversion of spin angular momentum to orbital angular momentum and polarisation structure vorticity, mediated by the longitudinal field. The results show the promise of an anisotropic metamaterial platform for manipulation of polarisation properties of and spin-orbit coupling in vector vortex beams.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • High-Q and FOM Dual-Band Polarization Dependent Ultra-Narrowband Terahertz
           Metamaterial Sensor

    • Authors: E. Manikandan;K. A. Karthigeyan;A. Arivarasi;E. Papanasam;
      Pages: 1 - 6
      Abstract: Polarization-dependent dual-band THz metamaterial using a modified Trishul structure is proposed in this paper. The absorber has three layers namely, a conducting ground plane, a dielectric substrate, and a structure top metallic patch. The top and bottom metallic is made up of gold material and the dielectric substrate is polyimide. The characteristics are obtained using the finite element method. The structure has obtained two resonant peaks at 0.78 THz(f1) and 1.65 THz(f2) for the X-polarized wave and at 0.81 THz(f3) and 1.53 THz(f4) for the Y-polarized wave respectively. The simulation result reveals that the absorber has obtained ultra-narrow band absorption with a full width half maximum(FWHM) of 4.8 GHz, 10 GHz, 5 GHz, and 10 GHz for f1, f2, f3, and f4 respectively. In addition, the underlying physical mechanism of the multi-band characteristics is analyzed using electric field and surface current distributions. The proposed absorber design has importance in the emerging THz system for polarization imaging and sensing applications. Also, flexible metamaterials could be useful for soft robotics applications also.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Single Longitudinal Mode and Widely Tunable Er:Y2O3 Ceramic Laser at ∼
           2.7 μm

    • Authors: Manman Ding;Xuanxi Li;Fei Wang;Jun Wang;Deyuan Shen;Dingyuan Tang;Heyuan Zhu;
      Pages: 1 - 4
      Abstract: We report on single-longitudinal-mode and tunable operation of an Er:Y2O3 ceramic laser at ∼2.7 μm using intracavity Fabry-Perot etalons combined with a birefringent filter. The laser is pumped with a high brightness, narrow linewidth diode source at ∼980 nm and generated over 240 mW of linearly polarized output power at 2717 nm for an absorbed pump power of 5.1 W. The wavelength tuning range demonstrated was spanned from 2708.6 nm–2741.2 nm, with output powers of>220 mW in the whole tuning range.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • A Novel Bidirectional Output Oscillating-Amplifying Integrated Fiber Laser
           With 2 Ports × 2 kW Level Near-Single-Mode Output

    • Authors: Jiaqi Liu;Lingfa Zeng;Peng Wang;Baolai Yang;Xiaoming Xi;Chen Shi;Hanwei Zhang;Xiaolin Wang;Fengjie Xi;
      Pages: 1 - 9
      Abstract: A novel bidirectional output oscillating-amplifying integrated fiber laser which combines the advantages of the bidirectional output fiber laser oscillator and the oscillating-amplifying integrated fiber laser is proposed and demonstrated experimentally. The influences of the reflectivities and center wavelengths of FBGs on the laser output power and efficiency were studied theoretically. The characteristics of the output laser were studied in detail in experiment. Based on this structure, we finally demonstrated a bidirectional laser output of 2 × 2-kW level with an active fiber length of 6 m for the oscillating section and 7 m for the amplifying section at both ends. The optical-to-optical conversion efficiency is 80.4%. The beam qualities of both ends are ${M}_{A}^{2}sim 1.3$ and ${M}_{B}^{2}sim 1.4$, which indicates a near-single-mode output. To the best of our knowledge, it was the first time that this structure has been proposed, and its feasibility was demonstrated experimentally.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Transverse Photonic Crystal Mode Engineering for Broad-Area Semiconductor
           Lasers With Narrow-Divergence Angles

    • Authors: Ting Fu;Yufei Wang;Xuyan Zhou;Jingxuan Chen;Xueyou Wang;Xiaoxu Xing;Liang Wang;Yingqiu Dai;Hongwei Qu;Aiyi Qi;Mingjin Wang;Wanhua Zheng;
      Pages: 1 - 5
      Abstract: Broad-area semiconductor lasers, coupled with asymmetric transverse photonic crystals (TPCs), are designed by the effective index method and the transfer matrix method. Due to the propagation constant of the fundamental mode lying in the forbidden band of the TPCs, but those of the high-order modes lying in the allowed band of the TPCs, the fundamental mode is mainly concentrated in the active ridge waveguide, while all the high-order modes extend into the lossy TPCs on both sides of the active ridge waveguide. Therefore, the fundamental mode possesses larger optical confinement factor than those of the high-order modes, and reaches the lasing threshold more easily, which is demonstrated by the single-lobe horizontal far-field pattern of the TPC broad-area laser under an injection current of 0.3 A near the threshold. The proposed TPC broad-area laser provides a new strategy of designing broad-area semiconductor lasers with narrow divergence angles.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Towards Cryophotonics: Experimental Characterization of SOA at Cryogenic
           Temperatures

    • Authors: Maeva Franco;Pascal Morel;Arnaud Gardelein;Ammar Sharaiha;
      Pages: 1 - 10
      Abstract: We present an experimental system study of the influence of cryogenic temperatures on the performance of a commercial Semiconductor Optical Amplifier (SOA) over the range 240 K – 70 K. Significant performance improvements were observed when the SOA is in cryogenic conditions. At 70 K and 100 mA we were able to measure a gain as high as 52 dB. At 240 K, only 50 mA of input current are necessary to reach a gain of 37 dB, and a noise figure of 3.8 dB, close to the theoretical limit. The SOA efficiency at power saturation, rises from 2.2% at ambient temperature up to 41% at 100 mA and 120 K.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Amplification of GaSb-Based Diode Lasers in an Erbium-Doped Fluoride Fibre
           Amplifier

    • Authors: Nikolai B. Chichkov;Amit Yadav;Franck Joulain;Solenn Cozic;Semyon V. Smirnov;Leon Shterengas;Julian Scheuermann;Robert Weih;Johannes Koeth;Sven Höfling;Ulf Hinze;Samuel Poulain;Edik U. Rafailov;
      Pages: 1 - 7
      Abstract: Building upon recent advances in GaSb-based diode lasers and Er-doped fluoride fibre technologies, this article demonstrates for the first time the fibre-based amplification of mid-infrared diode lasers in the wavelength range around 2.78 $mu$m. The laser setup consists of a GaSb-based diode laser and a single-stage Er-doped fibre amplifier. Amplification is investigated for continuous wave (CW) and ns-pulsed input signals, generated by gain-modulation of the GaSb-based seed lasers. The experimental results include the demonstration of output powers up to 0.9 W, pulse durations as short as 20 ns, and pulse repetition rates up to 1 MHz. Additionally, the amplification of commercial and custom-made GaSb-based seed lasers is compared and the impact of different fibre end-cap materials on laser performance is analysed.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • On-Chip Topological Multichannel Filtering and Routing Device Based on
           Synthetic Dimension

    • Authors: Zhihao Feng;Hongyi Yuan;Hongyu Zhang;Yuefeng Zhao;
      Pages: 1 - 5
      Abstract: On-chip topological nanophotonic filtering and routing devices are important components of integrated nanophotonic chip. The device filters topological photonic states with multiple frequencies and routes them into different output ports, respectively. However, there is no effective method to implement such devices to date. Here, an on-chip topological five-channel filtering and routing device is realized for the first time. Topological edge states are constructed based on synthetic dimension, which can use dielectric materials to construct topological photonic states without external magnetic field. This method has advantages including simple structure, easy integration, and high signal-to-noise ratio. The implementation of on-chip topological multichannel filtering and routing device is of great significance to the development of topological nanophotonic devices.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Sub-Micron Monolithic Full-Color Nanorod LEDs on A Single Substrate

    • Authors: Sung-Un Kim;Jeong-Kyun Oh;Dae-Young Um;Bagavath Chandran;Cheul-Ro Lee;Yong-Ho Ra;
      Pages: 1 - 5
      Abstract: The extended reality (XR) display, including augmented reality (AR) and virtual reality (VR), requires ultrahigh-resolution and high-luminance pixel technology. GaN-based micro-LEDs are the most promising for high-density pixel applications. However, it is necessary to simultaneously fabricate full-color R/G/B emitters on a single substrate. Moreover, the efficiency droop at long wavelengths with high-indium InGaN still remains a challenge. The InGaN nanorod has the potential to realize monolithic R/G/B LEDs on a single substrate, and the Al reflector has a light reflectance that can dramatically improve light extraction efficiency. Here, we designed sub-micron monolithic full-color R/G/B nanorod LEDs with an Al core-shell reflector on single chip. The optimal structures for light confinement and vertical light extraction by single InGaN nanorod R/G/B LED structures were identified. The single nanorod with Al core-shell structure dramatically increased the light extraction efficiency, and showed an improvement of more than 20%, especially in the red wavelength. As a result, by introducing a long-length nanorod structure, we have successfully designed a new submicron pixel with full-color R/G/B LEDs operating within 1 μm × 1 μm size. This unique design will be a key factor in enabling the next generation of AR and VR displays that require ultra-small and compact pixels.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Configurable Spin Orbital Interaction Utilizing Vector Beam Interference

    • Authors: Wei Liu;Zhen Chai;Kebin Shi;Ze Zhang;
      Pages: 1 - 6
      Abstract: Spin-orbit interaction (SOI) of light has attracted enormous interest for its potential applications in controlling light at nanoscale and holds promise for future optical information technology and optoelectronics. In particular, the transverse spin in evanescent waves is regarded as distinct manifestation of SOI and an emerging candidate for miniaturizing optoelectronic circuits. However, further application has been hampered by the inability to conveniently generate light field with configurable transverse spin. Here, we present a simple method to generate free-space light field with arbitrary transverse spin utilizing vector beam interference and numerically demonstrate the configurable spin orbital coupling in nanophotonic waveguide. Chiral waveguide with excellent extinction ratio up to 42 dB is achieved in our simulation. The propagating direction of guided mode can be fully controlled via tuning the ellipticity of transverse spin. The device is compatible with existing integrated nanophotonic devices and may find valuable applications in future optical information processing and optical communication technology.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Broadband Wavelength Conversion for Hybrid Multiplexing Signals Based on a
           Parallel Dispersion-Engineered Silicon Waveguide

    • Authors: Baobao Chen;Yi Zhao;Haoyang Tan;Xiaowei Guan;Shiming Gao;
      Pages: 1 - 7
      Abstract: Broadband all-optical wavelength conversion (AOWC) for hybrid wavelength- and mode-division multiplexing (WDM-MDM) signals is experimentally demonstrated based on degenerate four-wave mixing in a silicon chip with a parallel dispersion-optimized multimode nonlinear waveguide and mode (de)multiplexers. By simultaneously coupling two modes into the waveguide using an optical fiber array, the intermodal crosstalk is measured to be as low as −25.9 dB for the fundamental mode of the transverse electric mode (TE0) (or −23.6 dB for the first-order mode TE1), and the conversion efficiency is −25.4 dB for TE0 (or −26.3 dB for TE1) mode. A wide conversion bandwidth of ∼68 nm is measured except for the influence of the crosstalk, which is the first time to experimentally demonstrate the broadband wavelength conversion for MDM signal. Using a 4 × 10 Gbit/s on-off keying (OOK) hybrid WDM-MDM signal, four AOWC channels are obtained on the idlers and the power penalty of each channel is less than 2.7 dB at the bit-error-ratio of 1 × 10−9.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Dynamics of Dark Pulse Affected by Higher-Order Effects in Microresonators

    • Authors: Wenmi Shi;Zhiheng Li;Xuening Fan;Qiyuan Sun;Mulong Liu;Huimin Huang;Zhizhou Lu;Wei Zhao;
      Pages: 1 - 7
      Abstract: We theoretically investigate dynamics of dark pulse and Raman-Kerr microcombs generation influenced by higher-order effects, including high-order dispersion (HOD), stimulated Raman scattering (SRS) and self-steepening (SS) effects in silicon microresonators. These three effects cause the delay of dark pulse individually, or interact with each other to alter the drift velocity and direction of pulses. HOD effect can change pulse shift direction and even cause bifurcation. The temporal drift induced by SS or SRS effects could be balanced by the simultaneous third-order dispersion (TOD) engineering. In spectral domain, stable Raman-Kerr frequency comb will be generated due to the competition between strong SRS and Kerr effects. The Raman comb components are suppressed when HOD effect coexists, while SS effect has ignorable effect on the distribution of the Raman comb. Furthermore, the SS effect will increase the total energy of the spectrum by shifting the dispersive wave (DW) generation to the longer wavelength side. Our findings could deepen the understanding of intracavity nonlinear dynamics and provide theoretical guidance to precisely control the stabilization of dark pulse and the generation of broadband mid-infrared (MIR) microcomb.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • $_{2}$ +Nanodisk+System&rft.title=IEEE+Photonics+Journal&rft.issn=1943-0655&rft.date=2023&rft.volume=15&rft.spage=1&rft.epage=7&rft.aulast=Liu;&rft.aufirst=Zhao-Shi&rft.au=Zhao-Shi+Deng;Ling-Yan+Li;Chun-Lian+You;Yu-Wei+Lu;Jing-Feng+Liu;">Effective Modes for a Strongly Coupled Quantum Emitter-MoS $_{2}$ Nanodisk
           System

    • Authors: Zhao-Shi Deng;Ling-Yan Li;Chun-Lian You;Yu-Wei Lu;Jing-Feng Liu;
      Pages: 1 - 7
      Abstract: We present an effective modes theory for studying the strong light-matter interaction and better understanding the non-Markovian dynamics of a quantum emitter (QE) coupled to two-dimensional materials. Specifically, we investigate the spontaneous emission of a V-type QE in close proximity to a MoS$_{2}$ nanodisk. The non-Markovian population dynamics is observed and found linked to the initial states, indicating that the coupled system enters the strong-coupling regime. The effective modes analysis shows that though a dozen of resonant modes appear in the photonic density of states, only a few modes have significant contribution to the population dynamics. Our work demonstrates the effective modes theory as a powerful tool to explore and optimize the quantum states control of QE by two-dimensional materials.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Curved Computer-Generated Integral Imaging Based on Backward Ray-Tracing
           Technique

    • Authors: Hang Wang;Huan Deng;Zhaoda Guo;Cuini Yang;Chongji Zhao;
      Pages: 1 - 6
      Abstract: In traditional computer-generated integral imaging (CGII) methods, the generated elemental image array (EIA) is flat, and it doesn't fit for curved integral imaging (II) systems. Here, a curved CGII method was proposed for curved II system. In the proposed method, multiple virtual camera arrays (VCAs) were built up to determine the origins and directions of the traced rays. Combined with the backward ray-tracing (BRT) technique, a curved EIA was generated, and the rendering time was the same as the BRT-CGII of flat II system. A curved II system consisting of a curved organic light emitting diode display screen, a curved lens array and a curved optical diffuser screen was built up in the experiment. The proposed curved CGII method generated correct curved EIA for the curved II system, and the system presented vivid 3D images with the viewing angle as wide as 80° × 50°.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Complex Correlated Phase Gradient Variance Based Optical Coherence
           Tomography Angiography

    • Authors: Guoqiang Chen;Wen'ai Wang;Yanqiu Li;
      Pages: 1 - 9
      Abstract: In this study, we reported a complex-signal-based optical coherence tomography angiography (OCTA) method, called complex correlated phase gradient variance (CCPGV), for mapping high-quality microvascular images. The performance of the newly proposed algorithm is benchmarked against the previously reported phase-resolved Doppler variance, complex differential variance (CDV), and split-spectrum amplitude and phase-gradient angiography (SSAPGA), by both tissue phantoms experiments and in vivo human skin measurements. Compared to the phase-resolved Doppler variance, CCPGV can intrinsically reject undesirable phase shifts caused by bulk motion and trigger jitter. In contrast to CDV and SSAPGA, which are insensitive to phase instability, CCPGV can provide superior motion contrast, as demonstrated by ∼1.4 and 3 times higher contrast in phantom experiments respectively. An increase of 27.3% and 106.3% were found in vivo experiments for CCPGV, making it easier to distinguish vessels from the background static. Benefiting from the advantages, more vessels and better connectivity can be visualized in the en-face angiogram processed by the CCPGV method. We believe that our method will benefit the biomedical community to some extent in disease diagnosis and monitoring.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Polarization-Insensitive, Broadband, and Tunable Terahertz Absorber Using
           Slotted-Square Graphene Meta-Rings

    • Authors: Subhan Zakir;Rana Muhammad Hasan Bilal;Muhammad Ashar Naveed;Muhammad Abuzar Baqir;Muhammad Usman Ali Khan;Muhammad Mahmood Ali;Muhammad Ahsan Saeed;Muhammad Qasim Mehmood;Yehia Massoud;
      Pages: 1 - 8
      Abstract: Graphene-based metamaterials are gaining popularity for developing various reconfigurable and electrically tunable optical devices – especially in terahertz (THz) and infrared (IR) bands. Therefore, in this paper, we aim to investigate the broadband metamaterial-based absorber that efficiently absorbs the THz radiation ranging from 2.2 to 4.6 THz. The proposed absorber comprises a simple meta-square ring of graphene, which possesses different slots in its structure to induce multiple plasmonic resonances. It is observed that the proposed absorber manifests above 95% absorption for the normally incident THz waves, and it also maintains its absorption value over 80% for different obliquely incident operating conditions. Furthermore, the proposed absorber shows polarization-insensitive features. In addition, the absorption characteristics regulate from 95% to 15% by adjusting the chemical potential of graphene from 1 eV to 0.1 eV. Some of the salient features of the proposed absorber is largest reported bandwidth for single layer absorber with smallest footprint without sacrificing polarization insensitivity or amplitude tunability. From the application point of view, it could provide the pathway for implementing switching, cloaking, smart absorbers, and detection phenomena in the THz range.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Ultra-Broadband Spectrally Selective Absorber for Solar Thermal Absorption
           Based on TiN Square-Ring Meta-Structure

    • Authors: Ziang Gao;Shilin Yu;Zihao Li;Dafa Pan;Zhengshan Xu;Tonggang Zhao;
      Pages: 1 - 7
      Abstract: Based on the TiN square-ring structure, a spectrally selective absorber for solar thermal absorption is proposed announcing an average absorption of 95.69% in the major solar spectral region (280 nm∼2500 nm). When the wavelength exceeds 2500 nm, the absorption declines rapidly and decreases to 40.4% at the wavelength of 4000 nm, showing excellent spectral selectivity. As the incident angle of TE or TM polarized wave varies in a range of 0∼60 degrees, the proposed absorber maintains more than 90% solar absorption efficiency, which proves the insensitivity of incident angle and polarization angle. With operating temperature T = 300 K and solar concentrating coefficient C = 1, the solar-thermal conversion efficiency of the proposed absorber is 93.92%. At a high temperature of 700 °C, the solar-thermal conversion efficiency can maintain more than 80% at the condition of C = 200, demonstrating good thermal tolerance. It is believed that the proposed absorber has great potential to be applied in solar thermal absorption systems.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Switchable Wideband Terahertz Absorber Based on Refractory and Vanadium
           Dioxide Metamaterials

    • Authors: Jinglei Wang;Yu Yao;Xiaoshan Liu;Guiqiang Liu;Zhengqi Liu;
      Pages: 1 - 6
      Abstract: Achieving actively tunable metamaterial absorption is a significant development direction. Phase-transition materials have attracted growing interest for the use in nanophotonics owing to their flexibility. In this work, we firstly demonstrate a wideband terahertz refractory absorber that achieves more than 90% absorptance in the range of 1.71--3.31 THz. The metal composing the structure is refractory metal, which could function in high-temperature conditions and complex electromagnetic environment. Then, we incorporate phase-change material vanadium dioxide (VO2) film to this refractory absorber, realizing high reflection of more than 93% in the metallic state, while the wideband perfect absorption peak over 98% is obtained in the insulating state. Calculated results show that metamaterial absorber obtains switchable functions. Furthermore, the tunable absorber has polarization-insensitive behavior. So, our designed absorber with dynamic tunable characteristics provides flexibility to adjust the absorption performance and has significant value in application. The proposed architecture offers a novel method for creating dynamic and multi-functional photonic devices in phase-change materials.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Time-Stable Receiving System With Local Digitization Based on a Dithered
           Sample Clock

    • Authors: Kai Wang;Wei Wei;Danyang Wang;Pengyu Wang;Weilin Xie;Yi Dong;
      Pages: 1 - 6
      Abstract: We present a time-stable receiving system for broadband signals transmitted via a 25 km fiber optic link. The timing jitter of the signal induced by the transmission link is precisely eliminated after the signal is digitized with a dithered sample clock. The dithered clock is generated from the phase of a voltage-controlled oscillator, introducing the same transmission timing jitter of the link. Therefore, it can withstand an unlimited range of transmission delay variations without using any optical or electrical delay lines. Experimentally, binary phase-shift keying signals with bandwidths of several hundred MHz and different carrier frequencies are transmitted and received by the proposed system. The root mean square of the calculated timing jitters of the received signals is decreased to the order of picosecond. The simple remote end and immunity to environmental perturbations of the proposed scheme make it an ideal candidate for a large-scale distributed antenna system.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • A Multiband Microwave Photonic Filter Based on a Strongly Coupled
           Microring Resonator With Adjustable Bandwidth

    • Authors: Yuan Chen;ZhiQiang Fan;Yue Lin;Di Jiang;Xiang Li;Qi Qiu;
      Pages: 1 - 6
      Abstract: A bandwidth-tunable multiband microwave photonic filter (MPF) using a strongly coupled microring resonator (MRR) with optical phase modulation is demonstrated theoretically and experimentally. Two notches of the MRR adjacent to the optical carrier break the intrinsic balance of the phase-modulated signal and then two sub-MPFs are formed thanks to the conversion from phase modulation to intensity modulation (PM-IM). The frequency responses of the two sub-MPFs are superimposed to form a passband with a fixed center frequency. Due to the periodicity of the MRR transmission spectrum, multiple passbands separated by a certain spacing appear in the frequency domain and combine to form a multiband MPF, whose bandwidth can be adjusted by tuning the wavelength of the carrier. The tunable bandwidth and shape factors ranging from 0.73 GHz to 2.73 GHz and 5.06 to 1.38 are experimentally performed. The number of passbands can be reconfigured. The proposed multiband MPF has the potential to be employed in modern multi-standard wireless communication systems.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Optical Microwave Waveforms Generation Based on the Round-Trip Phase of
           the DFB Laser

    • Authors: Congbiao Lei;Wenyang Yuan;Guangcheng Zhong;Yuxuan Jiang;Mingqi Jiao;Jiaqi Yao;Liang Xie;
      Pages: 1 - 6
      Abstract: In this paper, we theoretically and experimentally analyze the influence of the round-trip phase of distributed feedback (DFB) lasers on the harmonic-phase of photocurrent, caused by the external injection current. The results indicate that the harmonic-phase of photocurrent introduced by the round-trip phase (HPIRP) reduces with the increase of modulation depth at a fixed frequency. Then, based on the HPIRP of the DFB laser, a simple photonic generation method of optical microwave waveforms is proposed and verified. In this scheme, three lasers with different wavelengths are mainly used. By adjusting the tunable optical delay lines and attenuators, the amplitude and phase of the photocurrent of the three branches converted by the photodetector (PD) can be controlled individually. The photocurrent of the superposition of the three branches can be controlled properly to form the target waveform. Dispersive elements and complex microwave photonic filtering are not required. Through experiments, rectangular and triangular waveforms with a repetition frequency of 3.75 GHz are generated.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Photonic Pseudospin Skyrmion in Momentum Space

    • Authors: Min Lin;Luping Du;Xiaocong Yuan;
      Pages: 1 - 6
      Abstract: Magnetic Skyrmions are topologically protected spin structures with sophisticated swirls of electron spins. In recent times, photonic counterparts of the magnetic Skyrmions have been discovered with new deep-subwavelength characteristics promising for future applications in optical information storage and transfer. While the photonic Skyrmions in real space have been observed in diverse photonic systems, studies on the photonic Skyrmions in momentum space have rarely been done. Here we show different forms of pseudospin Skyrmion around the Dirac point in momentum space of photonic crystals with the Kagome and honeycomb lattice. The pseudospin Skyrmions in momentum space are directly related to the topologically nontrivial states and manipulated by the inter-cell and intra-cell interactions between cylinders of the photonic crystal. The observation of the pseudospin Skyrmion in momentum space is expected to be valuable for manipulation of the flows and polarizations of light in topologically robust ways.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Bistable Reflection Assisted by Fano Resonance in DMDMW With Low-Threshold
           and Large Modulation Depth

    • Authors: ZhiXian Ni;Xianping Wang;Huiping Xu;Cheng Yin;Xin Xie;ChengYu Wu;Jun Li;Wen Yuan;MingHuang Sang;
      Pages: 1 - 20
      Abstract: Owing to an additional thinner planar waveguide with micron scale is attracted to the symmetrical metal cladding waveguide (SMCW) with sub-millimeter scale, the interference interaction between different Q-value guided modes would generate a Fano reflectivity curve. In our double metal-dielectric-metal waveguides (DMDMW) structure, a Kerr nonlinear medium is located in the guiding layer of the SMCW where the excited oscillating wave is enormously enhanced. Numerical calculations show that a minute variation of the incident light intensity will give rise to a change in the dielectric constant of the Kerr nonlinear medium and lead to positive feedback. A bistable reflection can be achieved with a low threshold and a large modulation depth because of the sharpness and the asymmetricity of the Fano reflectivity curve.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Ultra-Low Crosstalk and Fabrication-Tolerant Silicon-Nitride O-Band
           (de)Multiplexer Using Bragg Grating-Assisted Contra-Directional Coupler

    • Authors: Kuo-Fang Chung;Tien-Tsorng Shih;Jiun-Haw Lee;Ding-Wei Huang;
      Pages: 1 - 9
      Abstract: A wavelength division (de)multiplexing (WDM) filter with ultra-low channel crosstalk (XT) and high tolerance was proposed for a 1 × 4 O-band coarse-WDM (CWDM) system on a silicon-on-insulator (SOI). The filter consists of four waveguide Bragg grating (WBG) structures, each one having a multi-mode waveguide and corrugations at both waveguide side walls. To relax the critical dimension, low-material-index silicon nitride (SiN$_{x}$) was utilized instead of silicon. For efficient design of each SiN$_{x}$ multi-mode WBG (MMWBG), the core and corrugation widths were engineered over the perturbed-permittivity coupled-mode theory, leading to an ultra-high side-lobe suppression ratio $>$25.3 dB. The overall CWDM filter offers flat-top responses with ultra-low excess losses (ELs) $< $0.6 dB, a high channel uniformity $>-$0.45 dB, broad 1-dB bandwidths (BWs) $sim$13.45 nm, ultra-low XTs $
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • High-Density and Low-Crosstalk Multilayer Silicon Nitride Waveguide
           Superlattices With Air Gaps

    • Authors: Wen-ling Li;Jing-wei Liu;Guo-an Cheng;Rui-ting Zheng;Xiao-ling Wu;
      Pages: 1 - 7
      Abstract: High-density and low-crosstalk waveguide arrays are critical components in optical phased arrays (OPAs) and are widely used in solid-state light detection and ranging (LiDAR). In this work, silicon nitride waveguide superlattices with air gaps are proposed and analyzed theoretically. Mode analysis shows that the introduced air gaps beside the waveguide help shorten the skin depth of the evanescent field and increase the effective index range of the waveguide under single mode conditions. Lower crosstalk is demonstrated between a pair of waveguides with air gaps compared with those without air gaps. On this basis, a waveguide superlattice with air gaps is designed by combining the eigenmode expansion method and particle swarm optimization. The crosstalk of the waveguide superlattice is optimized to −24.3 dB when the waveguide pitch is 0.9 $mu text{m}$, the propagation length is 1 mm, and the wavelength is 905 nm. The crosstalk is still below −22.4 dB under the typical process variations and over the wavelength range of 890 nm–920 nm. Therefore, the proposed air-gap waveguide superlattices with high density and low crosstalk offer opportunities to improve the beam steering performance of OPA chips in the near-infrared (NIR) waveband.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Impact of Application Characteristics on Laser Energy Fluctuation in
           Integrated Photonic Switching Systems

    • Authors: Kang Wang;Huaxi Gu;Yintang Yang;Kun Wang;Yue Wang;
      Pages: 1 - 12
      Abstract: Laser energy cost is one of the primary energy budgets in integrated photonic switching systems. Traditional photonic switch testing injects random traffic to the switches, which only generates a “static” laser energy cost result. However, the laser's energy per bit performance fluctuates due to different process mapping scenarios of applications. In this paper, we did experiments to study the influence of the application's process mapping on the photonic switches' injection traces. Then we built a model to show the connection between the traces and the laser's energy per bit performance. To get the energy fluctuation results quickly and accurately, we propose a heuristic-based energy boundary searching methodology, with the model we built being considered. We also analyze the speedup and convergence of the methodology. Two photonic switches are studied under five kinds of application traces. The study shows an over 60% searching speedup and 90% accuracy in most cases, compared with the enumeration method, and the lasers' energy fluctuations vary from nearly 0% to over 150%. We further analyze the factors inducing such huge fluctuation variations, and a qualitative criterion that predicts the magnitude of the variations is proposed and discussed.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Miniaturized Optical System for a Caesium Satellite-Borne Cold Atom Clock

    • Authors: Yating Wang;Meifeng Ye;Xiaojun Jiang;Yanling Meng;Lin Li;Gongxun Dong;Wangdi Qiu;Jing Wu;Yiming Miao;Zhu Zhu;Tang Li;Liang Liu;Qiuzhi Qu;
      Pages: 1 - 7
      Abstract: We present a highly stable and miniaturised optical system designed for a caesium satellite-borne cold atom clock (CSCAC). The optical system was integrated on a $224,{mathop{rm mm}nolimits} times 195,{mathop{rm mm}nolimits} times 112,{mathop{rm mm}nolimits} $ aluminium-based silicon carbide bench and emitted laser beams with four different frequencies on three fiber ports to capture, cool, prepare, and detect atoms. The optical system, utilizing a compact three-layer optical-mechanical and thermal management design, passed environmental simulation tests and adapted to a special satellite-borne environment. The optical system stability meets the laser requirements of the clock.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Compact and Highly Sensitive Refractive Index Sensor Based on Embedded
           Double-Ring Resonator Using Vernier Effect

    • Authors: Xiao Xia Ma;Zhi Ying Zhao;Hao Yao;Jia Yao Deng;Jie Yun Wu;Zhe Feng Hu;Kai Xin Chen;
      Pages: 1 - 9
      Abstract: A compact and highly sensitive liquid refractive index (RI) sensor using Vernier effect achieved with embedded double-ring resonator is proposed and demonstrated. Unlike these conventional sensors using cascaded double-ring resonators to achieve Vernier effect, in our proposed embedded double-ring sensor (EDRS) the sensing ring is embedded on the reference ring, which makes the sensor more compact while achieving high sensitivity. Our typical fabricated EDRS with polymer material, which has a footprint of 1500 μm × 850 μm, achieves the RI sensitivity as high as 7390 nm/RIU in aqueous medium, which is in excellent agreement with the theoretical one.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Defect Engineering of TlPt2S3 for Highly
           Polarization-Sensitive Photodetector

    • Authors: Wenyue Wang;Fangqi Liu;Jian Shi;Zixin Yang;Tongtong Wang;Bin Liu;Qiang Yu;Sicong Zhu;Xianping Wang;Jian Wu;
      Pages: 1 - 6
      Abstract: Photodetectors based on two-dimensional materials exhibit excellent performance including high specific detectivity and fast response times. However, the polarization detection performance remains to be improved. Here, we propose a strategy to improve the polarization sensitivity of TlPt2S3-based photodetectors by defect engineering based on density functional theory (DFT) calculations and investigate their optoelectronic properties using quantum transport simulations at 0.2 V bias. Theoretical calculations show that the monolayer TlPt2S3 achieves a multifunctional output of the optoelectronic device and obtains a larger photocurrent and high extinction ratio by defect engineering under linearly polarized light irradiation. These results indicate that TlPt2S3 is expected to be one of the candidate materials for future optoelectronics and polarized light devices.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Design of High-Speed UTC-PD With Optimization of Its Electron Transit
           Performance and Parasitic Capacitance

    • Authors: Xiaowen Dong;Kai Liu;Yongqing Huang;Xiaofeng Duan;Qi Wang;Xiaomin Ren;
      Pages: 1 - 9
      Abstract: An 1500 nm thick collector layer is adopted in the uni-travelling-carrier photodiode (UTC-PD) to reduce the PD's capacitance, while the PD's diameter is set to be 20 μm for better saturation performance and optical coupling characteristic of a signal from a single mode fiber. By optimizing biasing voltage and input light intensity, the electric field intensity in the collector layer would be controlled to make the photo-generated electron in the UTC-PD transiting at around its peak drift velocity in the collector layer and at the same time to make the UTC-PD obtaining it minimum capacitance. Together with the optimization of the doping distribution in UTC-PD's cliff layer and its collector layer, the UTC-PD's high-speed performance and saturation performance can be further improved. An optimized 20 μm diameter UTC-PD with a simulated 106 GHz 3 dB bandwidth and 21.02 dBm output RF power at 25 GHz is designed. It proposes a discussion to realize high speed, high saturation performance UTC-PD together with high coupling efficiency from a single mode optical fiber by bringing the electric field determined drift velocity performance of its uni-traveling- carrier, the electron, into full play.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • High-Performance Lateral Metal-Germanium-Metal SWIR Photodetectors Using
           a-Si:H Interlayer for Dark Current Reduction

    • Authors: Harshvardhan Kumar;Chu-Hsuan Lin;
      Pages: 1 - 8
      Abstract: In this work, we propose the lateral metal-germanium-metal photodetectors (PDs) structure on the silicon-on-insulator platform for short-wave infrared (SWIR) applications. The proposed device utilizes the highly n-doped amorphous silicon (a-Si:H) interlayer between metallic contact and low n-doped germanium active region to achieve a low dark current. Additionally, the tuning of Schottky barrier height (SBH) by the selection of various metallic contacts (Cr/W/Mo) has been investigated in order to achieve a large reduction in dark current. With a-Si:H interlayer and Mo metallic contacts at both anode and cathode terminals, the simulated energy band diagram shows that an effective increase in SBH of 0.17 eV and 0.766 eV for electrons and holes, respectively, and thus acts as barriers for electron and hole dark currents. The result shows that the Mo metallic contact device manifests the least dark current (dark current density) of 0.27 pA (0.027 mA/cm2) at Vbias of 0.25 V and compared to Cr contact, it has been significantly decreased by two orders of magnitude. In addition, with Mo contact, the proposed device achieves the photogenerated-to-dark current $( {{I}_{ph}/{I}_{dark}} )$ ratio and the responsivity of $sim 1.7 times {10}^6$ and 0.96 A/W, respectively at λ = 1.55 μm with Vbias of 0.25 V. Furthermore, the proposed Mo-Ge-Mo PD shows high detectivity (NEP) of $9 times {10}^{11}$ cmHz1/2W−1 ($sim 3 times {10}^{ - 16}$WHz
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Design and Demodulation of a Fiber-Optic Fabry-Perot Sensor Applied in a
           High- Frequency Pneumatic System

    • Authors: Jianli Yang;Qian Yang;Shengchao Chen;Sufen Ren;Guanjun Wang;Mengxing Huang;
      Pages: 1 - 9
      Abstract: This study proposes a high-frequency pneumatic system and demodulation method based on polydimethylsiloxane (PDMS) film-embedded fiber-optic Fabry-Perot sensor to meet the conflicting requirements of small sizes and wide frequency-response range not achieved by conventional pneumatic probes. The high modulus of elasticity of PDMS films provides the potential for an upper limit of a pneumatic frequency response up to 20 kHz, and the new demodulation algorithm, based on the ability of the F-P cavity to return to its initial length from the maximum cavity length change, is utilized to analyze its variation. The process of recovering F-P cavity corresponds with the sparse part of the signal, which takes advantage of the unique characteristics of interference fringes in this part. Moreover, the relationship between the relative change of the F-P cavity length and pneumatic pressure, as well as the relationship between the duration of the relative change of the F-P cavity length and the frequency are analyzed comprehensively. The rationality of the proposed demodulation scheme is verified from the angle-error analyses. These analyses could be helpful for integrated and high-frequency response pneumatic detection.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Characteristics Measurement in a Deep UV Single Photon Detector Based on a
           TE-cooled 4H-SiC APD

    • Authors: In-Ho Bae;Seongchong Park;Kee-Suk Hong;Dong-Hoon Lee;
      Pages: 1 - 6
      Abstract: We report on the characteristics of a lab-assembled UV single photon detector based on a thermoelectrically cooled silicon carbide (4H-SiC) avalanche photodiode (APD). The SiC- APD in this experiment was fabricated with a beveled mesa structure, with electronics designed to achieve passive Geiger-mode operation and to convert the avalanche signal to a transistor–transistor logic signal by readout backend. We attached the SiC-APD to a 4-stage thermoelectric cooler to vary APD temperature from 25 °C to −30 °C, and investigated dark count rates according to applied bias voltage at different temperatures. Breakdown voltages applied to the SiC-APD were also measured while adjusting APD temperature. Finally, we evaluated afterpulse characteristics through the time-correlated single-photon counting method, and observed that afterpulsing probability increases with decreasing APD temperature.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Curvature Sensing-Based Pupil Alignment Method for Large-Aperture
           Telescopes

    • Authors: Qichang An;Hanfu Zhang;Xiaoxia Wu;Jianli Wang;Tao Chen;Guohao Ju;
      Pages: 1 - 5
      Abstract: In optical systems, pupil alignment is an important component of wavefront sensing, closed-loop feedback, and imaging vignetting control because it directly affects the detection limit of the system and thus the realization of scientific goals. This study proposes the use of the energy transfer characteristics of the pupil edge to determine the misalignment of each pupil. The mechanism involves decoupling the influence of each pupil from the final exit pupil energy distribution by using aperture coding without the addition of other optical paths. The degree to which the pupil is aligned is characterized by the normalized point source sensitivity (PSSn). The pupil misalignment PSSn increased from 0.75 to 0.83. The results of this study can be used to perform tomographic detection of pupil alignment and obtain high-quality telescopic images.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Highly Precise Magnetic Field Measurement Based RF-Assisted Sagnac
           Interferometer With Tapered Fiber

    • Authors: Sanfeng Gu;Danqi Feng;Yangxu Tang;Zhonghao Li;Xinhao Nan;Tianqi Wang;Ming Deng;
      Pages: 1 - 9
      Abstract: A radio frequency (RF)-assisted Sagnac interferometer based on a dual-loop optoelectronic oscillator (OEO) is experimentally demonstrated for high-precision magnetic field measurement, in which the tapered fiber covered with the magnetic fluid (MF) as the magnetic field sensing head is embedded in the Sagnac interferometer. The evanescent field of the tapered fiber can interact with the MF under the external magnetic field to cause the birefringence variation of the fundamental mode, leading to the change in the free spectral range (FSR) of the interferometer, which can be mapped to the oscillation frequency shift of the OEO in the microwave domain. By the above converting, the magnetic field measurement with high interrogation speed and resolution can be realized. In addition, the designed device shows a certain measurement directionality of the magnetic field due to two orthogonally polarized fundamental modes asymmetric to the magnetic field, obtaining a good conformity with the constructed theoretical models. The experimental results show the maximum magnetic field sensitivities of 159.4 Hz/mT in the range of 8.48-27.83 mT, and 350.8 Hz/mT in the range of 0-5.14 mT, corresponding to the light wave vector parallel and perpendicular to the magnetic field, respectively.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Novel Wide-Range Frequency Offset Estimation and Compensation for
           Burst-mode CPFSK Upstream Signaling in TDM-Based Digital Coherent PON

    • Authors: Takuya Kanai;Ryo Koma;Masamichi Fujiwara;Jun-ichi Kani;Tomoaki Yoshida;
      Pages: 1 - 8
      Abstract: The burst-mode continuous phase frequency shift-keying (CPFSK) transmitter that combines a directly modulated laser diode, an electro absorption modulator and a semiconductor optical amplifier is attractive as a cost-effective transmitter for phase modulation formats for digital signal processing (DSP)-based coherent passive optical network (PON) upstream signaling. However, since highly accurate wavelength controllers for the transmitters in optical network units (ONUs) create excessive cost burdens, large carrier frequency offsets (CFOs) must be expected. Thus, a CFO compensation method with wide compensation range is required. This paper proposes a novel CFO estimation and compensation method for burst-mode CPFSK signals in upstream PON signaling. The proposed method is based on a simple blind algorithm and does not require any training symbols. We demonstrate wide CFO compensation range, from −12 to 14 GHz, with high receiver sensitivity, less than −42.5 dBm for 10 Gbit/s binary CPFSK signals. This range far exceeds that of the conventional CFO compensation method using a blind algorithm. Moreover, the proposed method can enhance the convergence of finite impulse response (FIR) filters. The feasibility of the proposed CFO compensation technique is successfully demonstrated for burst-mode CPFSK signals.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • LCOS-Based 3 × 3 Folded Wavelength Selective Switch With
           High-Resolution Spectral

    • Authors: Bing Yu;Yunshu Gao;Genxiang Chen;
      Pages: 1 - 5
      Abstract: We propose and experimentally verify a 3 × 3 folded wavelength selective switch (WSS) scheme based on liquid crystal on silicon spatial light modulator (LCOS-SLM). This scheme adopts a concise double-layer folded structure that greatly reduced the structural complexity of the WSS system by using the same set of optical elements to accomplish twice beam deflection. The presented WSS is for the C-band, insertion loss is less than 13.2 dB, the spectral resolution is 1 GHz, the bandwidth tuning range is 16.25∼3750 GHz.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Free-Space Optical Communication Based on Mode Diversity Reception Using a
           Nonmode Selective Photonic Lantern and Equal Gain Combining

    • Authors: Feng Wang;Cong Qiu;Meiling Zhang;Guijun Hu;
      Pages: 1 - 7
      Abstract: This paper experimentally investigates the perform-ance of free-space optical (FSO) communication based on mode diversity reception (MDR) using nonmode selective photonic lantern (NSPL) and equal gain combining (EGC). By employing a mode demultiplexer and combining technology in the receiver, the bit error rate (BER) and outage performance of FSO communication system can be significantly improved. However, different from diversity system with multiple receive apertures, the branches in mode diversity system are non-independent fading signals, which are influenced by not only atmospheric but also the modal crosstalk of mode demultiplexer. Therefore, we take into consideration the difference of mode demultiplexer and study four schemes for FSO mode diversity reception system: 1) NSPL with equal gain combining (NSPL-EGC), 2) NSPL with maximal ratio combining (NSPL-MRC), 3) mode selective photonic lantern with equal gain combining (MSPL-EGC), and 4) mode selective photonic lantern with equal gain combining (MSPL-MRC). Experimental results show that NSPL-EGC is the most suitable scheme for MDR with low implementation complexity, and the performance difference is less than 1 dB compared with the one using MRC at BER = 3.8×10−3 under turbulence from weak to strong.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • All-Optical Regeneration and Format Conversion for 4APSK Signals Based on
           Nonlinear Effects in HNLF

    • Authors: Qiankun Li;Huashun Wen;Jiali Yang;Qi Xu;Xiongwei Yang;Yameng Li;
      Pages: 1 - 9
      Abstract: An all-optical format conversion and regeneration scheme about 4-ary amplitude and phase shift keying (4APSK) signals is proposed and numerically simulated based on nonlinear effects in the high nonlinear fiber (HNLF). The input 4APSK signal is firstly converted into a regular quadrature phase shift keying (QPSK) signal by the nonlinear Mach-Zehnder interferometer (MZI) based on the self-phase modulation (SPM). Secondly, a degenerate phase-sensitive amplification (PSA) based on the four-wave mixing (FWM) is utilized to convert the regular-QPSK into two binary phase shift keying (BPSK) signals. The nonlinear MZI configuration is also used to compress the amplitude noise of BPSK. Thirdly, one phase shifter and one variable optical attenuator (VOA) are used to adjust the relative phase and power relationships of the two amplitude-regenerated BPSK signals. The regenerated 4APSK and converted QPSK signals can be generated in one 3-dB optical coupler through coherent addition of the two regenerated BPSK signals. The error-vector-magnitude (EVM) and the bit-error-rate (BER) are calculated and compared to evaluate the scheme performance. The proposed scheme can be applied as an optical regenerator or format convertor at the network gateway to increase the transmission distance or connect optical networks with different modulation formats.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Impact of the Refractive Index on the Achievable Rate of Liquid
           Crystal-Based Digital-RIS Indoor VLC Systems

    • Authors: Alain R. Ndjiongue;Telex M. N. Ngatched;Octavia A. Dobre;
      Pages: 1 - 6
      Abstract: In wireless networks, reconfigurable intelligent surfaces (RISs) have recently been proven to have a significant impact. The RIS has been incorporated into wireless communication systems to improve security, increase coverage, reduce interference, and improve transmission quality. Digital RIS (DRISs) have also proven to provide better reflection management. However, the impact of the DRIS intrinsic parameters on the system's achievable rate, has not yet been investigated. Due to their availability and easily reconfigurable properties, liquid crystals (LCs) appear as suitable materials for use in DRIS, specifically in optical communication systems. This paper analyzes the effect of the LC's refractive index on the achievable rate of LC-based DRIS indoor visible light communication systems. Based on a set of discrete phase shifts, required refractive indices have been evaluated. The reflected power and achievable rates are determined with respect to incoming light wavelengths at 510 nm, 550 nm, and 670 nm. According to the obtained numerical results, there is no linear relationship between refractive indices, corresponding transition coefficients, phase shifts, light power, and achievable rate.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • A Bidirectional WDM-PON Free Space Optical (FSO) System for Fronthaul 5 G
           C-RAN Networks

    • Authors: Fady El-Nahal;Tianhua Xu;Dokhyl AlQahtani;Mark Leeson;
      Pages: 1 - 10
      Abstract: High-speed cellular technologies require low-latency and high-capacity optical networks. The Centralized Radio Access Network (C-RAN) architecture offers a cost-effective solution for mobile network deployment. To maximize flexibility and minimize deployment costs of fronthaul networks, we propose a hybrid bidirectional fronthaul C-RAN topology based on Wavelength Division Multiplexing (WDM) passive optical networks (PONs) and free space optical communication (FSO). The wavelength reuse scheme utilized here relies on reflective semiconductor optical amplifiers (RSOAs) to reduce cost and increase capacity. The system was demonstrated for 20 Gbps 16$-$quadrature amplitude modulation (16-QAM) intensity-modulated orthogonal frequency-division multiplexing (OFDM) downstream signals and 5 Gbps On-off keying (OOK) upstream signals, respectively. A Gamma-Gamma channel model is used to demonstrate optical signal transmission over an FSO link. The bit error rate (BER) results indicate that the hybrid WDM-PON-FSO based fronthaul architecture could achieve 320 Gbps over 20 km of single-mode fiber (SMF) and 700 m free space transmission.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Distribution Matching for Dimming Control in Visible-Light
           Region-of-Interest Signaling

    • Authors: Phuc Duc Nguyen;Yoshifumi Shiraki;Kenji Ishikawa;Jun Muramatsu;Noboru Harada;Takehiro Moriya;
      Pages: 1 - 14
      Abstract: We propose a two-level dimmer based on binary distribution matching where a low-rate signal controls the output probability distribution of a high-rate bit sequence, which can be used in region-of-interest (RoI) signaling applications. To reduce the rate loss of the dimmer, we propose the extended multiset-partition distribution matching (EMPDM) algorithm with a novel binary-tree-structure implementation. In addition, we introduce 4p-EMPDM, a compact version of EMPDM, which has a typical composition (TC) and four leading composition pairs (CPs). The codebook of 4p-EMPDM includes only run-length-aware codewords, which reduces the maximum run-length of the transmitted bit sequence by 4.27 times. Hence, it guarantees flicker mitigation for visible-light RoI signaling systems at 6 kHz without using any run-length limited code (non-RLL). Using experimental data collected from the low-rate RoI signaling prototype, we introduced a threshold range where both intensity and area information of the received training symbols can be exploited to optimize the shaping ratios of the 4p-EMPDM dimmer. Because of the non-RLL feature, the proposed system can support soft-decision forward-error-correction (FEC) decoding to improve reliability. Our system outperforms related systems based on hybrid modulation schemes in terms of spectral efficiency, bit rate, and minimum required optical clock rate.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • A Power-Domain MST Scheme With BPPM in NLOS Ultraviolet Communications

    • Authors: Tian Cao;Tianfeng Wu;Changyong Pan;Jian Song;
      Pages: 1 - 10
      Abstract: Due to the high path loss of non-line-of-sight (NLOS) ultraviolet communications (UVC) channel, pulse modulation schemes, such as on-off keying (OOK) and M-ary pulse-position modulation (PPM), and photon-counting receivers are commonly adopted. Although M-ary PPM can be demodulated and decoded without the channel state information, its spectral efficiency is lower than OOK's. To improve the spectral efficiency of M-ary PPM in NLOS UVC, a power-domain multilayer-superposed transmission (MST) scheme with binary PPM (BPPM) is proposed in this work. Based on this scheme, the signal in each layer can be directly decoded without successive interference cancellation, which is necessary for other MST schemes in the power domain. Hence, a low complexity receiver in the NLOS UVC system can be realized. Additionally, the bit-error rate (BER) and achievable data rate (ADR) expressions of the proposed MST scheme are derived. Monte-Carlo simulations are performed to verify the analytical BER expression. The NLOS UVC system performance employing the proposed MST scheme is further demonstrated and compared with pure BPPM. The results indicate that with the optimal power allocation factor for each layer, the overall ADR of the NLOS UVC system with the proposed power-domain MST scheme can surpass that with pure BPPM.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Asymmetrically Clipped Optical Hadamard Coded Modulation (ACO-HCM)

    • Authors: Henrik Schulze;Peter A. Hoeher;
      Pages: 1 - 12
      Abstract: In many optical wireless communications systems, power efficiency is paramount. In others, flexibility is important. To achieve these goals, this paper presents a novel transmission scheme dubbed asymmetrically clipped optical Hadamard coded modulation (ACO-HCM). ACO-HCM combines the characteristics of real-valued non-negative orthogonal frequency-division multiplexing (OFDM) and Hadamard coded modulation (HCM). Unlike OFDM, which is based on the Fourier transform and therefore delivers a continuous waveform, ACO-HCM provides a discrete set of amplitudes. This feature is desirable for nonlinear channels. Error probabilities are analytically calculated for a linear receiver similar to the decorrelation receiver in direct-sequence code-division multiple access (DS-CDMA). Maximum-likelihood sequence estimation is also investigated and shown to outperform the linear receiver, particularly in the presence of a time-dispersive channel. The peak-to-average power ratio of ACO-HCM is derived for the electrical as well as the optical domain in closed form.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Intelligent Reflecting Surfaces for Underwater Visible Light
           Communications

    • Authors: Yalçın Ata;Hanaa Abumarshoud;Lina Bariah;Sami Muhaidat;Muhammad Ali Imran;
      Pages: 1 - 10
      Abstract: Intelligent reflecting surfaces (IRSs) offer paradigm shift towards enhancing the capabilities of wireless communications. The use of this emerging technology in the realm of underwater wireless systems is a promising solution to overcome the limitations pertinent to such challenging environments. In this paper, we quantify the performance enhancement offered by the integration of IRS technology in the context of underwater optical wireless communication (OWC). Specifically, we derive a closed-form expression for the outage probability over log-normal channels, taking into consideration the underwater attenuation, pointing error, and turbulence effects. The underwater turbulent medium is characterized by the recently introduced Oceanic Turbulence Optical Power Spectrum (OTOPS) model that uses the practical values of average temperature and salinity concentration in earth basins. The presented numerical results take into account the effects of the turbulent medium as well as the communication system parameters (i.e., communication range, receiver aperture diameter, number of IRS). Our results show that IRSs can offer significant enhancement in the reliability of underwater OWC systems under attenuation, beam displacement, and turbulence effects. Moreover, the combined effect of using a large number of reflecting surfaces and a larger aperture diameter yields a more noticeable improvement.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • High Bandwidth Semi-Polar InGaN/GaN Micro-LEDs With Low Current Injection
           for Visible Light Communication

    • Authors: Feifan Xu;Pengjiang Qiu;Tao Tao;Pengfei Tian;Xiaoyan Liu;Ting Zhi;Zili Xie;Bin Liu;Rong Zhang;
      Pages: 1 - 4
      Abstract: Micro-light-emitting diodes (micro-LEDs) with high modulation rates and low power consumption could attract growing attention as visible light communication (VLC) technology advances. The designed and fabricated semi-polar micro-LEDs have achieved high bandwidth at low current injection due to the reduced quantum-confined Stark effect (QCSE), which was significantly greater than that of typical c-plane at the same current injection. Semi-polar green micro-LEDs got a −3 dB bandwidth that surpasses 500 MHz and 1 GHz at low current densities of 43.8 A/cm2 and 120.6 A/cm2, while blue micro-LEDs exceed 500 MHz at low current densities of 76.6 A/cm2, respectively. Additionally, the free space VLC system has shown semi-polar blue and green micro-LED transmission data rates of 3.495 Gbps (433 A/cm2) and 3.483 Gbps (402 A/cm2) respectively. Semi-polar micro-LEDs, which can achieve low power consumption and high bandwidth, are anticipated to play a significant role in the development of energy-efficient VLC in the future.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Secure Optical Image Communication Using Double Random Transformation and
           Memristive Chaos

    • Authors: Heping Wen;Jiahao Wu;Linchao Ma;Zhen Liu;Yiting Lin;Limengnan Zhou;Huilin Jian;Wenxing Lin;Linhao Liu;Tianle Zheng;Chongfu Zhang;
      Pages: 1 - 11
      Abstract: The issue of information security in photonics environment has attracted more and more attention, especially when the secure communication of optical digital images has become a research hotspot. In this paper, we propose a hybrid encryption scheme for color images in the frequency and spatial domains based on double random transform and memristor hyperchaotic system. Firstly, we decompose the color image into RGB channels and then perform fast fourier transform (FFT) to transform the digital image from the spatial domain to the frequency domain. Secondly, two-phase masks are generated using the memristor hyperchaotic system, and the Fresnel diffraction optical transformation method is performed twice for encryption. Thirdly, the transformation from the frequency domain to the spatial domain is completed using inverse fast fourier transform (IFFT). Finally, the image is permuted and diffused using the chaotic sequences to obtain the final cipher image. Double random phase encryption expands the key space, while the combination of spatial and frequency domains improves the resistance to attacks. Based on cryptanalysis theory, we introduce a dynamic key associated with plain image, which can effectively resist plain attack. The experimental results show that the optical digital image encryption scheme has a large key space, excellent comprehensive performance, and can resist common attacks. In addition, we verify the hardware feasibility and ease of implementation of the proposed algorithm in an embedded optical communication network experimental platform. Therefore, our proposed scheme in this paper is a preferred optical digital image secure communication technology scheme with good application prospects.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Vision-Based Target Detection and Positioning Approach for Underwater
           Robots

    • Authors: Yanli Li;Weidong Liu;Le Li;Wenbo Zhang;Jingming Xu;Huifeng Jiao;
      Pages: 1 - 12
      Abstract: The accurate target detection under different environmental conditions and the real-time target positioning are vital for the successful accomplishment of underwater missions of Remotely operated vehicles (ROVs). In this paper, we propose a vision-based underwater target detection and positioning approach to detect and estimate the position and attitude of artificial underwater targets. The proposed approach is composed of an underwater target detection algorithm YOLO-T and a target positioning algorithm. Firstly, we modify the structure of YOLOv5 algorithm using Ghost module and SE attention module to improve the calculation time of target detection. Secondly, a series of image processing operations are performed on the improved YOLOv5 detection results to increase the detection accuracy. Thirdly, a cooperative marker is designed as the artificial underwater target, and the corresponding positioning algorithm is presented to calculated the position and attitude of the target according to the geometric information of the designed marker. We validate our approach through experimental tests respectively in a water tank, an anechoic tank, and the sea trial in Huanghai Sea in China. The results demonstrate the accurate performance of the proposed detection and positioning method.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Design of Integrating Sphere Uniform Light System for Solar Simulator

    • Authors: Jiali Chen;Gaofei Sun;Shi Liu;Guoyu Zhang;Siwen Chen;Jierui Zhang;Qiang Liu;
      Pages: 1 - 7
      Abstract: In the process of designing and adjusting the solar simulator, the side lobe effect and aberration of the optical integrator affect the irradiation uniformity, an integrating sphere is proposed to replace the optical integrator for uniform light and the compound parabolic reflector for beam shaping. First, based on the equal illuminance theorem and the radiation transfer theory, the calculation formula of the energy transmission efficiency of the porous integrating sphere is derived; Then, the light hole illuminance interference factor is introduced, and the effects of the aperture size of the integrating sphere, the radius of the integrating sphere, and the size and position of the baffle on the energy transmission efficiency and irradiation uniformity are analyzed. Finally, an integrating sphere uniform light system with high energy transmission efficiency and uniformity is designed and simulated with LightTools software. The simulation results show that: the average difference of irradiation uniformity and the range difference of irradiation uniformity are closest to 1 in the area where the ratio of the opening size and radius of the integrating sphere is 36%–40%, and the light is evenly distributed; When the baffle position is 0.8 times of integrating sphere radius away from the light entrance hole, irradiation non-uniformity at the outlet hole is 1.99%, which is the best position of the baffle; In the effective irradiation surface of Φ1032 mm, the irradiation non-uniformity is 1.98%, and the maximum irradiance is 0.62 solar constants, the spot simulation with high irradiation uniformity on large irradiation surface is realized.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Enhanced Light Extraction of Infrared AlGaAs-Based LEDs With Micron Array

    • Authors: Zhi-Wei Wen;Hong-Yi Lin;Mei-Jia Yang;Sen-Lin Li;Shuo Song;Shang-Feng Bao;Dong Sun;
      Pages: 1 - 5
      Abstract: In order to improve the light extraction efficiency (LEE) of a plane AlGaAs-based LED (Device A), three different surface periodic micron-scale arrays, micron pillar (Device B), micron truncated cone (Device C) and micron cone (Device D), are prepared by the conventional ultra-violet (UV) lithography. The morphology of the three devices B–D is characterized by a scanning electron microscopy (SEM). The periodic array structures improve the photon escape probabilities. In comparison to the Device A, the light output powers (LOPs) of the Devices B–D increase 54.0%, 145.5% and 157.2% at an injection current of 500 mA, respectively. Moreover, we use the Monte Carlo ray-tracing method to simulate the LEE of the four devices. The energy distribution of the Devices B-D is more concentrated in the middle region in contrast with the Device A.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Fourier Ptychography Reconstruction Based on Reweighted Amplitude Flow
           With Regularization by Denoising and Deep Decoder

    • Authors: Baopeng Li;Caiwen Ma;Okan K. Ersoy;Zhibin Pan;Wansha Wen;Zhonghan Sun;Wei Gao;
      Pages: 1 - 10
      Abstract: Fourier ptychography (FP) is a computational imaging technique with the advantage that it can obtain large field-of-view (FOV) and high-resolution (HR) imaging. We propose an algorithm for Fourier ptychography based on reweighted amplitude flow (RAF) with regularization by denoising (RED) and deep decoder (DD), which is an untrained deep generative model. The proposed method includes two loops, using reweighted amplitude flow with regularization by denoising as an inner loop for phase retrieval and deep decoder for further denoising as an outer loop in the Fourier ptychography recovery system. The proposed method does not need any training dataset, just adds a little computer time during the image recovery process. The proposed method has no bias due to training images, which is different from other deep learning methods. The experimental results show that the proposed method can improve the reconstruction quality in both PSNR and SSIM.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Optical Proximity Correction Using Machine Learning Assisted Human
           Decision

    • Authors: Albert Lin;Tejender Rawat;Chung-Yuan Chang;Han-Chun Tung;Hsueh-Li Liu;Peichen Yu;
      Pages: 1 - 9
      Abstract: Optical proximity correction (OPC) is a critical step in semiconductor manufacturing due to its high complexity and significant influence on the subsequent process steps. Conventional OPC using the Maxwell equation can become more and more challenging as a fully vectorized three-dimensional simulation is required for advanced technology nodes. Machine learning (ML) has been a promising alternative recently. This work proposes machine-learning-assisted human decision, which can be more in line with the clean room engineer's practice and can potentially surpass pure human decision and the pure machine learning approach. Using 10-step optimization in the photolithographic mask, the averaged mean square error (MSE) at the optimized cases are 6360 and 2101 for two-bar patterns and 7132 and 5931 for tri-line attackers when comparing pure human decision and ML-assisted human. The average MSEs at the first 3 steps are 26019 and 6023 for the two-bar pattern and 79979 and 7738 for the tri-line attacker when comparing pure ML and ML-assisted human. It is suggested that the strength of the ML-assisted human decision lies in the early-stage superiority over pure ML, flexibility, incorporating past experience, and a human sense that cannot be formulated concretely by statistical models.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
  • Coordinating Multiple Light-Trails in Multicast Elastic Optical Networks
           With Adaptive Modulation

    • Authors: Anliang Cai;Yongcheng Li;Jian Chen;Jianhua Shen;
      Pages: 1 - 10
      Abstract: Optical multicasting has been considered resource efficient for multicast services. Light-tree and light-trail are two technologies that support optical multicasting while the former requires many splitters and thus experiences significant power loss. In this paper, we consider using the light-trail technology for the accommodation of multicast requests in elastic optical networks with adaptive modulation. For better spectrum efficiency, we consider accommodating each multicast by multiple light-trails. We formulate the problem by Mixed Integer Linear Programming (MILP) and propose efficient heuristic algorithms. For the impact of accommodation sequence on the algorithm performance, apart from the traditional sequence among different requests, we consider an additional sequence among the destinations of a multicast. For efficient multicast accommodation, we propose several strategies and compare their performances through a range of cases. To avoid a destination occupying excessive resources in certain cases of joining multiple light-trails, we propose an efficient algorithm to delete some duplicated destinations. Numerical results show that the proposed heuristic algorithms significantly outperform a benchmark algorithm and one performs close to the optimal MILP. Also, the algorithm for deleting certain destination replicas largely reduces the spectrum and transmitter usages, up to 41% and 20% for the cases considered, respectively.
      PubDate: Feb. 2023
      Issue No: Vol. 15, No. 1 (2023)
       
 
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