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Inverse design of broadband and dispersion-flattened highly GeO2-doped optical fibers based on neural networks and particle swarm algorithm

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Optoelectronics Letters 2025年第6期21卷 328-335页

作者： LI Runrui WANG Chuncan Key Laboratory of All Optical Network and Advanced Telecommunication Network Ministry of Education Institute of Lightwave Technology Beijing Jiaotong University

Reverse design of highly GeO2-doped silica optical fibers with broadband and flat dispersion profiles is proposed using a neural network（NN） combined with a particle swarm optimization（PSO） ***,the NN model designed to predict optical fiber dispersion is trained with an appropriate choice of hyperparameters,achieving a root mean square error（RMSE） of 9.47×10-7on the test dataset,with a determination coefficient（R2） of ***,the NN is combined with the PSO algorithm for the inverse design of dispersion-flattened optical *** expand the search space and avoid particles becoming trapped in local optimal solutions,the PSO algorithm incorporates adaptive inertia weight updating and a simulated annealing ***,by using a suitable fitness function,the designed fibers exhibit flat group velocity dispersion（GVD） profiles at 1 400—2 400 nm,where the GVD fluctuations and minimum absolute GVD values are below 18 ps·nm-1·km-1and 7 ps·nm-1·km-1,respectively.

关键词： A

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Coherence analysis of noise-like pulses generated by an erbium-doped fiber mode-locked laser

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Optoelectronics Letters 2024年第4期20卷 205-210页

作者： ZHANG Ziyi WANG Chuncan LI Jing WANG Peng Key Laboratory of All Optical Network and Advanced Telecommunication Network Ministry of EducationInstitute of Lightwave TechnologyBeijing Jiaotong University Beijing 100044China

The noise-like pulses(NLPs)with tunable fraction of the pedestal height in the whole intensity autocorrelation(AC)trace are numerically demonstrated in the designed erbium-doped fiber(EDF)mode-locked laser,which contains the saturable absorber(SA)with nonlinear polarization rotation(NPR),sinusoidal-shaped or Gaussian-shaped filter,two segments of EDFs,and two pieces of single-mode fibers(SMFs)with normal dispersion and anomalous dispersion,*** pedestal ratio of the intensity AC trace can be tuned by changing the gain saturation energies of *** results show that when the net cavity dispersion is 1.06 ps^(2),the tuning range of the pedestal ratio for the NLPs can reach its maximum values,which are 0.51—0.89 and 0.58—0.88 for the sinusoidal-shaped and Gaussian-shaped filters,*** addition,an appropriate choice of filter bandwidth is also conducive to obtain a wide range of the tuning pedestal ratio for the intensity AC trace.

关键词： fiber tuning polarization

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A Dual-Polarized Fixed-Frequency Beam-Scanning Leaky-Wave Antenna for 5G Millimeter-Wave Applications

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IEEE Transactions on Antennas and Propagation 2025年第6期73卷 3666-3679页

作者： Wei, Bang Li, Zheng Xiong, Zhe Zhao, Yi Chen, Meie Wang, Junhong Beijing Jiaotong University Key Laboratory of All Optical Network and Advanced Telecommunication Network Ministry of Education Institute of Lightwave Technology Beijing100044 China WuHan Maritime Communication Research Institute China

In this paper, a dual-polarized (DP) fixed-frequency beam-scanning leaky-wave antenna (LWA) is presented. Operating from 24.5 to 27.5 GHz, the LWA consists of a vertically polarized (VP) patch array, a horizontally polarized (HP) printed dipole array, and a dual-channel gap waveguide (GW) that provides traveling-wave excitation. The VP patch array, located at the center of the antenna aperture, contains 80 slot-excited patches. The HP dipole array is divided into two subarrays distributed on both sides of the antenna aperture and is excited by slot-coupled microstrip lines. The VP and HP arrays are independent, enabling simultaneous control of both polarization beams. Due to the low profile of the printed dipole, the radiation aperture of the antenna can be fully utilized, providing the ability to expand in two dimensions. To achieve fixed-frequency beam scanning, each antenna unit has a 1-bit amplitude modulation capability, realized by electrically controlling the PIN diode. A dual-channel GW capable of transmitting both TE01 and TE10 modes is designed, and the stacked architecture makes it suitable for a compact DP antenna. Holographic method is employed to realize the beam scanning. Simulated and measured results verify that the proposed antenna can achieve fixed-frequency, wide-angle, and quasi-continuous beam scanning. © 1963-2012 IEEE.

关键词： Scanning antennas

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A 3D-Printed Simple Asymmetric Orthomode Transducer for Wideband THz Applications 12

A 3D-Printed Simple Asymmetric Orthomode Transducer for Wide...

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12th IEEE Asia-Pacific Conference on Antennas and Propagation, APCAP 2024

作者： Tan, Junyao Li, Yujian Wang, Junhong Beijing Jiaotong University Key Laboratory of All Optical Network and Advanced Telecommunication Network of Moe Beijing China

ISBN: (纸本)9798350351019

A novel compact asymmetric wideband orthomode transducer (OMT) design method is presented in this paper. The design employs an asymmetric geometry which is based on a T-waveguide transmission line. To address the issue of higher-order mode reflections typical of asymmetric structures, a novel T-shaped waveguide-to-waveguide transducer structure has been proposed. This new structure is compatible with both fundamental and higher-order modes, expanding the bandwidth of the OMT. To verify the design, the OMT is connected to a pyramidal horn and fabricated by micro-3D printing with a weight of only 0.35 g. Measured results demonstrate that the proposed OMT achieves a wide bandwidth of 53.9% (from 126 GHz to 219 GHz) and an isolation between the two ports of more than 50 dB. Benefitted from the compact structure and excellent performance, the new method would be an attractive candidate in the new generation of terahertz wireless communication systems. © 2024 IEEE.

关键词： Bandwidth

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Ultra-high bandwidth signal and pump wavelength division multiplexer based on all-dielectric metasurface 15

Ultra-high bandwidth signal and pump wavelength division mul...

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15th International Conference on Information Optics and Photonics, CIOP 2024

作者： Zhang, Shuyuan He, Kai Zheng, Jingjing Pei, Li Ning, Tigang Li, Jing Wang, Jianshuai Bai, Bing Hu, Zhouyi Key Laboratory of All Optical Network & Advanced Telecommunication Network of EMC Beijing Jiaotong University Beijing100044 China

ISBN: (数字)9781510686175

ISBN: (纸本)9781510686168

Metasurfaces are two-dimensional planar structures composed of artificial atoms with special electromagnetic properties in a certain arrangement, which can flexibly control the amplitude, phase, and polarization of incident light, and have strong light field manipulation capabilities, so they have attracted extensive attention. In this work, a WDM based on all-dielectric metasurface is proposed to realize the beam combination function of ultra-wideband signal and narrowband pumping. The WDM can realize the low-loss and high-efficiency wavelength division multiplexing function of one ultra-wideband signal and one or two narrowband pumps by punching holes in the fused silica thin layer, with a signal passing bandwidth of more than 400nm, almost no energy loss on the signal wavelength, a pump loss of less than 1dB, and a pump occupied bandwidth of less than 3nm. It can well solve the problem of serious limitation of signal bandwidth of the current wavelength division multiplexer, and provide important support for the key components and equipment of ultra-high bandwidth optical communication such as ultra-high bandwidth optical fiber amplifiers. © 2024 SPIE.

关键词： Fiber optic components

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Effect of endogenous pumping on amplification bandwidth broadening in bismuth-doped fiber amplifiers 15

Effect of endogenous pumping on amplification bandwidth broa...

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15th International Conference on Information Optics and Photonics, CIOP 2024

作者： Wu, Ge Wang, Lihong Zheng, Jingjing Pei, Li Ning, Tigang Li, Jing Wang, Jianshuai Bai, Bing Hu, Zhouyi Key Laboratory of All Optical Network & Advanced Telecommunication Network of EMC Beijing Jiaotong University Beijing100044 China

ISBN: (数字)9781510686175

ISBN: (纸本)9781510686168

The previous papers of the research group have already found that the excitation of a 1310 nm endogenous pump by signal feedback combined with a single fiber Bragg grating (FBG) under the condition of 1240 nm pumping can significantly enhance the gain effect of bismuth-doped fiber amplifiers (BDFA) at long wavelengths. In order to further clarify the effect of the endogenous pump generation mode and the different feedback mechanisms on the broadening effect, we have used a tunable dual grating combined with a controllable pump/signal feedback amplifier structure, and compare in detail the broadening characteristics under the different conditions mentioned above. The experimental results show that any form of endogenous pumping can result in amplification bandwidth expansion, but there is a difference in the behavior of the broadening due to the dual grating line cavity versus the grating-signal reflector line cavity, as well as in the degree to which the broadening is affected by the pump feedback. The effective utilization of this property can provide positive assistance in enhancing the gain-bandwidth performance of BDFA as well as in improving the transmission capacity of communication systems. © 2024 SPIE.

关键词： Fiber Bragg gratings

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Switchable down-,up-and dual-chirped microwave waveform generation with improved time–bandwidth product based on polarization modulation and phase encoding

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Chinese Physics B 2022年第7期31卷 620-628页

作者： Yuxiao Guo Muguang Wang Hongqian Mu Guofang Fan Institute of Lightwave Technology Key Laboratory of All Optical Network and Advanced Telecommunication NetworkMinistry of EducationBeijing Jiaotong UniversityBeijing 100044China

A switchable down-,up-and dual-chirped microwave waveform generation technique with improved time–bandwidth product(TBWP)is proposed and demonstrated based on a dual-polarization dual-parallel Mach–Zehnder modulator(DPDPMZM)cascaded with a polarization modulator(Pol M).By properly controlling the phase shifts of the radio frequency signals applied to the DP-DPMZM,switchable down-,up-and dual-chirped waveforms with simultaneous frequency and bandwidth doubling can be *** enlarge the TBWP further,splitting parabolic signal and phase-encoding splitting parabolic signal are used to drive the Pol M for the enhancement of bandwidth and time *** results demonstrate the generation of down-,up-and dual-chirped microwave waveform with TBWP of 8,160 and *** proposed method may find applications in future multifunction radar systems due to the high performance and flexibility.

关键词： microwave photonics linearly chirped waveform generation time–bandwidth product

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Highly sensitive magnetic field sensor based on a polarimetric fiber laser assisted by a Terfenol-D bar

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Optics Express 2025年第10期33卷 20816-20828页

作者： Xiao, Shiying Feng, Jinglin Wu, Beilei Wang, Xiaoxuan Jiang, Youchao Wang, Zixiao Institute of Lightwave Technology Key Laboratory of All Optical Network & Advanced Telecommunication Network Ministry of Education Beijing Jiaotong University Beijing100044 China School of Electronics and Information Engineering Beijing Jiaotong University Beijing100044 China

We propose a highly sensitive magnetic field sensor based on a polarimetric fiber laser and a Terfenol-D bar. The laser cavity is structured with a high birefringence Erbium-doped fiber (Hi-Bi EDF) and a pair of wavelength-matched fiber Bragg gratings (FBGs). To transduce the magnetic field variations, A Terfenol-D bar is strategically employed, stretching the sensing Hi-Bi EDF upon exposure to the external magnetic field. The induced stress on the Hi-Bi EDF subsequently triggers shifts in the polarimetric mode beat frequency (PMBF), which exhibit a direct and measurable correlation to the variations in the magnetic field intensity. The experimental results show that the proposed sensor features high sensitivity, linear response, and excellent repeatability. It is noteworthy that in three consecutive magnetic field testing experiments, the sensor achieved a magnetic field sensitivity of up to -7.83 MHz/mT in the linear range of 3-12 mT, which surpasses that of comparable sensors by at least one order of magnitude, demonstrating the superiority of this sensor in magnetic field sensing capability. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Magnetic levitation

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Design of a Radial Waveguide Omnidirectional Antenna 10

Design of a Radial Waveguide Omnidirectional Antenna

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10th IEEE International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, MAPE 2024

作者： Tang, Yanfei Li, Zheng Wang, Junhong Institute of Lightwave Technology Beijing Jiaotong University Key Laboratory of All Optical Network and Advanced Telecommunication Network Beijing100044 China

ISBN: (纸本)9798331533922

This paper presents the design of an omnidirectional antenna based on a radial waveguide. To achieve the matching between waveguide and free space, a horn structure is employed. The antenna is coaxially fed, and an inverted cone is employed in the parallel plate for impedance matching. The antenna has strong omnidirectional radiation characteristics and operates in the 3.6 GHz to 4.35 GHz frequency range. © 2024 IEEE.

关键词： Omnidirectional antennas

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Conformal Leaky-Wave Antenna with Scanning Beam Based on Spoof Surface Plasmon Polaritons 10

Conformal Leaky-Wave Antenna with Scanning Beam Based on Spo...

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10th IEEE International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, MAPE 2024

作者： Zhang, Bochao Li, Zheng Wang, Junhong Beijing Jiaotong University Key Laboratory of All Optical Network and Advanced Telecommunication Network Institute of Lightwave Technology Beijing100044 China

ISBN: (纸本)9798331533922

This paper presents a conformal leaky-wave antenna with scanning beam based on spoof surface plasmon polaritons (SSPPs). By utilizing the SSPPs to slow-wave propagation, the rectangular patch units distributed on two staggered layers are used as the radiating structure, and the scanning beam of the conformal leaky-wave antenna is achieved by controlling the on/off state of the PIN diodes on the units. Through simulation analysis, it is found that the antenna operates in the frequency band of 4.2 GHz to 5.5 GHz, and at the frequency of 5.4 GHz, it can achieve beam scanning at multiple angles in the - direction at θ=90°, with a side lobe level lower than -5dB and a realized gain of around 10dBi. The conformal antenna is suitable for operation on curved surfaces such as cylinders. © 2024 IEEE.

关键词： Scanning antennas

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