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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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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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Low Complexity Detection Algorithms Based on ADMIN for Massive MIMO

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China Communications 2023年第11期20卷 67-77页

作者： Shuchao Mi Jianyong Zhang Fengju Fan Baorui Yan Muguang Wang Institute of Lightwave Technology Beijing Jiaotong UniversityBeijing 100044China Key Lab of All Optical Network and Advanced Telecommunication of EMC Beijing Jiaotong UniversityBeijing 100044China

This paper proposes the alternating direction method of multipliers-based infinity-norm(ADMIN) with threshold(ADMIN-T) and with percentage(ADMIN-P) detection algorithms,which make full use of the distribution of the signal to interference plus noise ratio(SINR) for an uplink massive MIMO *** ADMIN-T and ADMIN-P detection algorithms are improved visions of the ADMIN detection algorithm,in which an appropriate SINR threshold in the ADMIN-T detection algorithm and a certain percentage in the ADMIN-P detection algorithm are designed to reduce the overall computational *** detected symbols are divided into two parts by the SINR threshold which is based on the cumulative probability density function(CDF) of SINR and a percentage,*** symbols in higher SINR part are detected by *** interference of these symbols is then cancelled by successive interference cancellation(SIC).Afterwards the remaining symbols with low SINR are iteratively detected by *** simulation results show that the ADMIIN-T and the ADMIN-P detection algorithms provide a significant performance gain compared with some recently proposed detection *** addition,the computational complexity of ADMIN-T and ADMIN-P are significantly ***,in the case of same number of transceiver antennas,the proposed algorithms have a higher performance compared with the case of asymmetric transceiver antennas.

关键词： ADMIN low complexity detection algo-rithm massive MIMO MMSE SINR

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Switchable instantaneous frequency measurement by optical power monitoring based on DP-QPSK modulator

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Chinese Physics B 2022年第4期31卷 336-347页

作者： Yu-Lin Zhu Bei-Lei Wu Jing Li Mu-Guang Wang Shi-Ying Xiao Feng-Ping Yan Institute of Lightwave Technology Key Laboratory of All Optical Network and Advanced Telecommunication of EMCBeijing Jiaotong UniversityBeijing 100044China

We propose and analyze an instantaneous frequency measurement system by using optical power monitoring technique with improved *** primary component adopted in the proposal is a dual-polarization quadrature phase shift keying(DP-QPSK) modulator which is used to modulate the microwave signal that has a designed time delay and phase *** generated optical signal is sent to polarization beam splitter(PBS) in DP-QPSK *** to the complementary transmission nature of polarization interference introduced by PBS,the frequency information is converted into the optical power and the relationship between the amplitude comparison function(ACF) and microwave frequency to be measured is ***,the frequency of the microwave signal can be easily measured through monitoring the optical powers of the two output ports of the ***,by adjusting the direct current(DC) biases of the DP-QPSK modulator instead of changing the electrical delay,the measurement range and resolution can be *** this paper,the basic principle of the instantaneous frequency measurement system is derived in detail,and simulation has been performed to investigate the resolution,the measurement range,and the influence of imperfection *** proposed scheme is wavelength-independent and its measurement range is switchable,which can avoid the laser wavelength drifting problem and thus greatly increasing the system flexibility.

关键词： microwave photonics DP-QPSK modulator instantaneous frequency measurement

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A distributed reception-based method for identifying vortex beams 8

A distributed reception-based method for identifying vortex ...

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8th International Conference on Speckle Metrology, Speckle 2023

作者： Su, Yongfu Jiang, Youchao Zhao, Yuzhen Wang, Zixiao Xiao, Shiying Key Laboratory of All Optical Network Advanced Telecommunication Network of Emc Institute of Lightwave Technology China Beijing Jiaotong University Beijing100044 China

ISBN: (数字)9781510674592

ISBN: (纸本)9781510674585

After the vortex beam is transmitted in the space laser communication scene for thousands or even tens of thousands of kilometers, the spot diameter will expand to several meters or even tens of meters, and the existing detection methods that require receiving the whole spot are no longer applicable. To address this problem, this paper proposes a distributed detection scheme to identify the topological charge of the vortex beam by analyzing and processing the data received from each detector. Matlab is used to simulate the proposed scheme. The vortex beam is a Laguerre-Gaussian beam with a transmission distance of 100 km, and the simulation analysis shows that the scheme can detect Laguerre-Gaussian beams with topological charge number -3 to +3. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Gaussian beams

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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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Instantaneous frequency measurement using two parallel I/Q modulators based on optical power monitoring

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Chinese Physics B 2022年第1期31卷 215-220页

作者： Chuangye Wang Tigang Ning Jing Li Li Pei Jingjing Zheng Jingchuan Zhang Key Laboratory of All Optical Network and Advanced Telecommunication Network of EMC Institute of Lightwave TechnologyBeijing Jiaotong UniversityBeijing 100044China Beijing Institute of Spacecraft Environment Engineering Beijing 100029China

A scheme for instantaneous frequency measurement(IFM)using two parallel I/Q modulators based on optical power monitoring is *** amplitude comparison function(ACF)can be constructed to establish the relationship between the frequency of radio frequency(RF)signal and the power ratio of two optical signals output by two I/Q *** frequency of RF signal can be derived by measuring the optical power of the optical signals output by two I/Q *** measurement range and measurement error can be adjusted by controlling the delay amount of the electrical delay *** feasibility of the scheme is verified,and the corresponding measurement range and measurement error of the system under different delay amounts of the electrical delay line are *** with previous IFM schemes,the structure of this scheme is *** devices,a photodetector and an electrical power meter are not used,which reduces the impact of the environmental disturbance on the system and the cost of the *** simulation,the measurement range can reach 0 GHz-24.5 GHz by adjusting the delay amount of the electrical delay lineτ=20 *** measurement error of the scheme is better at low frequency,and the measurement error of low frequency 0 GHz-9.6 GHz can reach-0.1 GHz to+0.05 GHz.

关键词： microwave photonics instantaneous frequency measurement optical power monitoring

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Low noise figure bismuth-doped fiber amplifier based on Sagnac comb filter 14

Low noise figure bismuth-doped fiber amplifier based on Sagn...

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14th International Conference on Information Optics and Photonics, CIOP 2023

作者： Hou, Wenqiang Pei, Li Zheng, Jingjing Wang, Jianshuai Ye, Xiao Wang, Dingchen Wang, Lihong Zhang, Fuhao Key Laboratory of All Optical Network and Advanced Telecommunication Network of EMC Institute of Lightwave Technology Beijing Jiaotong University Beijing100044 China

ISBN: (纸本)9781510671744

This paper presents a double-pass low-noise bismuth-doped fiber amplifier based on a Sagnac comb filter. The amplifier utilizes a Sagnac loop to filter out spontaneous emission light outside the signal wavelength, effectively decreasing the noise figure. Experimental results show that the amplifier achieves a minimum noise figure of only around 3.7 dB. Moreover, its gain bandwidth can cover a significant portion of the O-band. Under a forward pump power of 0.538 W, with an input signal power of -30 dBm, the amplifier can reach a gain of 29.6 dB, while the noise figure is only approximately 4 dB. Under backward pump, the gain difference for different input signal powers is larger compared to forward pump. We also studied the variation of gain with input signal power at a pump power of 0.5 W, using both forward and backward pump methods. The results indicate that the pump direction has a minor impact on the gain but significantly affects the noise figure, with the noise figure under forward pump being 1-2 dB lower than that under backward pump. Additionally, the amplifier exhibits a maximum saturation output power of approximately 9.5 dBm. In conclusion, this amplifier has great potential for application in WDM communication systems. © 2023 SPIE.

关键词： Noise figure

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