- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Cylindrical Vector Beam Fibre Laser Based on photonic lantern
摘要： We demonstrate a linear-cavity continuous-wave (CW) fibre laser generating cylindrical vector beams (CVBs) using a photonic lantern as transverse mode converter and mode splitter. The CVB fibre laser operates at a center wavelength of 1553.1 nm, with a 3 dB linewidth of less than 0.08 nm and a signal-to-background ratio of > 45 dB. The measured purity of the radially and azimuthally polarized beams is > 96%.
关键词： continuous-wave,Cylindrical Vector Beam,photonic lantern
更新于2025-11-28 14:24:03
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Sub-milliampere-threshold continuous wave operation of GaN-based vertical-cavity surface-emitting laser with lateral optical confinement by curved mirror
摘要： The continuous wave operation of a gallium-nitride-based vertical-cavity surface-emitting laser (GaN-based VCSEL) that uses boron ion implantation for lateral current confinement and a curved mirror for lateral optical confinement was investigated. The threshold current was 0.25 mA (Jth = 3.5 kA cm?2) for a 3 μm diameter current aperture at room temperature and the lasing wavelength was 445.3 nm. This is the lowest threshold current recorded for a GaN-based VCSEL. This result is considered to be a milestone for the further miniaturization of GaN-based VCSELs by the implementation of lateral optical confinement due to the incorporation of a curved mirror.
关键词： continuous wave operation,threshold current,lateral optical confinement,GaN-based VCSEL,curved mirror
更新于2025-11-28 14:23:57
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High-Power Continuous-Wave and Acousto-Optical Q-Switched Ho:(Sc <sub/>0.5</sub> Y <sub/>0.5</sub> ) <sub/>2</sub> SiO <sub/>5</sub> Laser Pumped by Laser Diode
摘要： We experimentally investigate the continuous-wave (cw) and acousto-optical (AO) Q-switched performance of a diode-pumped Ho:(Sc0.5Y0.5)2SiO5 (Ho:SYSO) laser. A fiber-coupled laser diode at 1.91 ??m is employed as the pump source. The cw Ho:SYSO laser produces 13.0 W output power at 2097.9 nm and 56.0% slope efficiency with respect to the absorbed pump power. In the AO Q-switched regime, at a pulse repetition frequency of 5 kHz, the Ho:SYSO laser yields 2.1 mJ pulse energy and 21 ns pulse width, resulting in a calculated peak power of 100 kW. In addition, at the maximum output level, the beam quality factor of the Q-switched Ho:SYSO laser is measured to be about 1.6.
关键词： Laser Diode Pumped,Continuous-Wave,Acousto-Optical Q-Switched,High-Power,Ho:(Sc0.5Y0.5)2SiO5 Laser
更新于2025-11-28 14:23:57
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Supercontinuum generation triggered by a weak 100-kHz linewidth continuous-wave
摘要： We experimentally and numerically demonstrate efficient supercontinuum generation in highly nonlinear dispersion-shifted fiber triggered by a weak 100-kHz linewidth continuous-wave at the 10-7 level relative to the pump, which is the lowest power reported.
关键词： Four-wave mixing,Nonlinear optics,Supercontinuum generation
更新于2025-11-28 14:23:57
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[IEEE 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Va?ster?s (2018.9.3-2018.9.6)] 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Train Communication System with Distributed Antenna System using Optical Frequency Doubler in 90 GHz Band
摘要： A MilliMeter Wave (MMW) backhaul technology for advanced high-speed trains running a tunnel for a long distance is under development for the communication gathering a large number of passenger communications transmitting to the ground. The authors are studying a system that realizes large capacity communication between trains and the ground by arranging Distributed Antenna System (DAS) along with a long distance railway. In order to transmit a radio signal between distant antennas and the main frame of base station physically, it is necessary to avoid the influence of fiber dispersion for Radio over Fiber (RoF) which transmits a radio signal over the light. We are investigating RoF system with optical multiplication which can obtain doubled frequency after transmission. In this paper, we develop the vector modulation signal transmission by the RoF used for the downlink of the base station and report on the result of the packet communication experiment with the base station and the terminal.
关键词： DAS,RoF,millimeter wave,Frequency multiplication
更新于2025-11-28 14:23:57
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Multipole Radiations from Large Gold Nanospheres Excited by Evanescent Wave
摘要： We proposed the use of the evanescent wave generated in a total internal reflection configuration to excite large gold nanospheres and investigated the radiations of the high-order plasmon modes supported in gold nanospheres. It was revealed that the evanescent wave excitation is equivalent to the excitation by using both the incident and reflected light, offering us the opportunity to control the orientation of the electric field used to excite nanoparticles. In addition, it was found that the scattering light intensity is greatly enhanced and the background noise is considerably suppressed, making it possible to detect the radiations from high-order plasmon modes. Moreover, the influence of the mirror images on the scattering induced by a metal substrate is eliminated as compared with the surface plasmon polariton excitation. By exciting a gold nanosphere with s-polarized light and detecting the scattering light with a p-polarized analyzer, we were able to reveal the radiation from the electric quadrupole mode of the gold nanosphere in both the spatial and the frequency domains. Our findings are important for characterizing the radiations from the high-order modes of large nanoparticles and useful for designing nanoscale photonic devices.
关键词： scattering,plasmon mode,electric dipole,radiation pattern,gold nanosphere,evanescent wave,electric octupole,electric quadrupole
更新于2025-11-21 11:24:58
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Low temperature fabrication of high quality gate insulator in metal-oxide-semiconductor capacitor using laser annealing
摘要： This paper reports the fabrication of a high quality gate oxide for metal-oxide-semiconductor field effect transistors using a continuous wave blue laser. A thin Zr metal layer was inserted between the dielectric and substrate to increase laser absorption and reduce the interface layer. A simulation of laser irradiation showed that metal layer insertion induces a significant increase in temperature during laser annealing compared to the dielectric without a metal layer. The laser annealed capacitor with a 1 nm-thick Zr metal layer showed superior electrical characteristics, such as high capacitance, low leakage current, low fixed charge density and low interface state density. Based on these results and the economic advantage of blue laser diodes, this technique can be a solution for low temperature processes, such as monolithic 3-dimensional integration, where low temperature processes are required.
关键词： 445 nm wavelength,Zirconium oxide,scavenging effect,laser anneal,blue,MOSCAP,continuous wave,visible laser
更新于2025-11-14 17:28:48
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Application of metasurfaces in the design of performance-enhanced low-profile antennas
摘要： This paper presents a review of metasurface-based antennas conducted at the Microwave Communication Laboratory (MCL) of Ajou University in the Republic of Korea. In this paper, pro?le miniaturization, bandwidth enhancement, multiband operation, and radiation pattern control of metasurface-based antennas are considered. The paper ?rst presents metasurface-based antennas implemented by placing various radiators on top of the metasurface. It then presents antennas implemented by placing the radiators below the metasurface with and without the ground plane. Metasurface-based antennas are not only able to achieve high ef?ciency with a low pro?le but they are also able to generate extra resonances from the metasurface structures, which signi?cantly enhances the overall performance of the antennas. These additional resonances were utilized in multiband and/or wideband operations. In addition, the design of a planar compact wide-gain-bandwidth metasurface-based antenna and its radiation characteristics are presented at a terahertz (THz) frequency range. The THz antennas were designed with metasurfaces and a planar leaky-wave feeding structure. Finally, the outlook on future research at the MCL for antenna-related work and their applications using metasurfaces is provided.
关键词： surface wave resonance,sequential rotation,crossed dipole,arti?cial magnetic conductor,metamaterial,wideband,circular polarization,leaky-wave,Antenna,array,metasurface
更新于2025-09-23 15:23:52
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Backward wave oscillation suppression study of the helix travelling wave tube
摘要： In this paper, the effect of backward wave oscillation (BWO) on helix slow wave structure performance for TWT has been described. In this paper both the cases tapered and untapered helix slow wave structure (SWS) have been analyzed, caused by BWO for high gain helix TWT. In house developed the one-dimensional (SUNRAY-1D) large signal analysis model has been used for stability analysis of the helix SWS. The analysis on backward wave amplifier gain has been carried out as a function of the taper parameter and frequency parameter. The position and nature of tapering also affect the electronic efficiency as well as the start oscillation current. Hence, position and nature of tapering have been optimized.
关键词： backward wave oscillation (BWO),support rods,instability,Slow wave structure (SWS)
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC) - Tainan, Taiwan (2018.11.5-2018.11.7)] 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC) - A CMOS 76-81 GHz 2TX 3RX FMCW Radar Transceiver Based on Mixed-Mode PLL Chirp Generator
摘要： A fully integrated 76-81 GHz frequency-modulated continuous-wave (FMCW) radar transceiver (TRX) in 65nm CMOS is presented. Two transmitters (TXs) and three receivers (RXs) are integrated for MIMO processing. A 38.5 GHz mixed-mode PLL with reconfigurable loop bandwidth and frequency doubling scheme are employed to generate the reconfigurable FMCW chirp waveforms. Passive voltage-mode down-conversion is utilized to improve the RX linearity against TX leakage. A bottom-switching PA is proposed to realize the Bi-Phase modulation, and the magnetically-coupled resonator technique is used to effectively expand the link bandwidth. Measurement results show that the FMCW TRX could generate reconfigurable chirps with the bandwidth from 250 MHz to 4 GHz and the period from 600 us to 10 ms. The root-mean-square (RMS) frequency error is less than 251 kHz. The TX maximum output power is 13.4 dBm and is adjustable within 3 dB by reconfiguring its LDO output voltage. The RX achieves 15.3 dB noise figure and -8.5 dBm RF input-referred PldB. Real-time experiments are carried out using the proposed TRX chip, in which the measured average distance error is 10 cm. The overall power consumption is 921mW with 2-TXs and 3-RXs powered on.
关键词： transceiver,PLL,CMOS,mm-wave,Radar,frequency-modulated continuous-wave (FMCW)
更新于2025-09-23 15:23:52