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International Conference on advanced Infocomm Technology (ICAIT)

作者： Junpeng Liang Gang Qiao Jinlong Wei Juhao Li Yu Yang Zhaopeng Xu Lulu Liu Shangcheng Wang Qi Wu Weisheng Hu Dept. of Circuits and System Peng Cheng Laboratory Shenzhen China State Key Lab of Advanced Optical Communication Systems and Network Peking University Beijing China

Micro-bending with random curvature is usually used to model the mode coupling in few mode fiber (FMF). However, previous models overlooked the accompanied mode dependent loss (MDL) and neglected the order constraints of coupling loss between different modes. In this work, we calculate out the accompanied loss of each mode by using the finite element method. The results show that MDL always increases with bending curvature due to the high-order modes have larger loss than low-order modes. This observation has been confirmed by experiments. Finally, we compare the multi-segment FMFs model with and without considering the accompanied MDL, the results show that micro-bending would degrade the system performance especially when considering the accompanied MDL.

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High-dimensional broadband non-Abelian holonomy in silicon nitride photonics

arXiv

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arXiv 2023年

作者： Chen, Youlv Guo, Xuhan Zhang, Xulin Su, Yikai State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University China State Key Laboratory of Integrated Optoelectronics College of Electronic Science and Engineering Jilin University Changchun China

Non-Abelian geometry phase has attracted significant attention for the robust holonomic unitary behavior exhibited, which arises from the degenerate subspace evolving along a trajectory in Hilbert space. It has been regarded as a promising approach for implementing topologically protected quantum computation and logic manipulation. However, due to the challenges associated with high-dimensional parameters manipulation, this matrix-valued geometry phase has not been realized on silicon integrated photonic platform, which is CMOS compatible and regarded as the most promising flatform for next-generation functional devices. Here, we demonstrate the first non-Abelian holonomic high-dimensional unitary matrices on multilayer silicon nitride integrated platform. By leveraging the advantage of integrated platform and geometry phase, ultracompact footprint, highest order (up to six) and broadband operation (larger than 100nm) non-Abelian holonomy unitary matrices are experimentally realized. Our work paves the way for versatile non-Abelian optical computing devices in integrated photonics. Copyright © 2023, The Authors. All rights reserved.

关键词： Geometry

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Ultrahigh-resolution fiber-optic sensing system with an ultra-simple system and broadband light

Ultrahigh-resolution fiber-optic sensing system with an ultr...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Shuting Liu Qingwen Liu Shuangxiang Zhao Shoulin Jiang Wei Jin Zuyuan He State Key Laboratory of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University Shanghai China Department of Electrical Engineering The Hong Kong Polytechnic University China

An ultra-simple fiber-optic sensing system is proposed. The resolution reached $99.6{\text{f}}\varepsilon /\sqrt {{\text{Hz}}} $ at 1kHz with an enhanced Sagnac interferometer, which is the highest resolution level of... 详细信息

ISBN: (纸本)9781957171258

关键词： Amplified spontaneous emission Erbium doped fiber amplifiers Fiber optic sensors Light sources Sagnac interferometry White light

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The Beam Optics Analysis Based on Monte Carlo Simulation of the Magnetic state Selection and optical Detection Cesium Beam Clock 12th

The Beam Optics Analysis Based on Monte Carlo Simulation of ...

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12th China Satellite Navigation Conference, CSNC 2021

作者： Chen, Sifei Xu, Shaohang Liu, Chang Li, Yuanhao Wang, Yanhui State Key Laboratory of Advanced Optical Communication System and Networks Department of Electronics Peking University Beijing100871 China Peking University Tianjin300450 China School of Physics Peking University Beijing100871 China

ISBN: (纸本)9789811631450

Compact cesium beam clocks are of great importance in navigation, time-keeping and precision measurements. In traditional cesium clocks, cesium atoms are deflected by strong inhomogeneous magnetic fields, whose velocity distribution and populations of different quantum states are altered. Normally, the distributions are hard to describe with analytical functions. An alternative solution is to apply the Monte Carlo simulation to sample the atoms and calculate the trajectories. We apply the method to cesium beam clocks based on the magnetic state selection and fluorescence detection scheme. The state distributions of the detectable atoms are obtained with Monte Carlo simulation inside the collimator and finite element simulation of the magnetic field. The performance of the cesium beam tube is also estimated via the sampled atoms, such as the signal amplitude and the signal-to-noise ratio (SNR) of atomic shot noise and laser frequency noise. The estimated SNR of the designed cesium beam tube is over 7000 in a 1 Hz detection bandwidth. The influence of the deflection angle of the collimator on the performance of the beam tube is analyzed. The method can be used to guide the design of the cesium beam tube and is easily applied to different cesium beam clocks. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Cesium

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Demonstration of a distributed feedback laser diode working as a graded-potential-signaling photonic neuron and its application to neuromorphic information processing

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Science China(Information Sciences) 2020年第6期63卷 176-183页

作者： Bowen MA Weiwen ZOU State Key Laboratory of Advanced Optical Communication Systems and Networks Intelligent Microwave Lightwave Integration Innovation Center (iMLic) Department of Electronic Engineering Shanghai Jiao Tong University

We find that a commonly-used distributed feedback laser diode(DFB-LD) can work as a gradedpotential-signaling photonic neuron. Through theoretical and experimental demonstration, DFB-LDs are proved useful for three graded-potential-signaling-based neuromorphic processing applications of the pattern recognition, the single-wavelength implementation of spike timing dependent plasticity(STDP), and the sound azimuth measurement. The pattern recognition with a full-width-at-half-maximum(FWHM) of 1 μs is realized in the experiment.

关键词： neuromorphic photonics graded-potential-signaling photonic neuron pattern recognition optical spike timing dependent plasticity sound azimuth measurement

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Multi-Modal Intelligent Channel Modeling: A New Modeling Paradigm via Synesthesia of Machines

arXiv

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arXiv 2024年

作者： Bai, Lu Huang, Ziwei Sun, Mingran Cheng, Xiang Cui, Lizhen Shandong University Jinan250101 China The State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Peking University Beijing100871 China The School of Software Shandong University Jinan250101 China

In the future sixth-generation (6G) era, to support accurate localization sensing and efficient communication link establishment for intelligent agents, a comprehensive understanding of the surrounding environment and proper channel modeling are indispensable. The existing method, which solely exploits radio frequency (RF) communication information, is difficult to accomplish accurate channel modeling, and hence cannot support the aforementioned application associated with intelligent agents. Fortunately, multi-modal devices are deployed on intelligent agents to obtain environmental features, which could further assist in channel modeling. Currently, some research efforts have been devoted to utilizing multi-modal information to facilitate channel modeling, while still lack a comprehensive review. To fill this gap, we embark on an initial endeavor with the goal of reviewing multi-modal intelligent channel modeling (MMICM) via Synesthesia of Machines (SoM), which refers to intelligent multi-modal sensing-communication integrated technology. In the MMICM, the multi-modal information from communication devices and various sensors is intelligently processed to explore the mapping relationship between communications and sensing. Compared to channel modeling approaches that solely utilize RF communication information, the utilization of multi-modal information can provide a more in-depth understanding of the propagation environment around the transceiver, thus facilitating more accurate channel modeling. First, this paper introduces existing channel modeling approaches from the perspective of the channel modeling evolution, i.e., starting from conventional channel modeling, the channel modeling approach moves on to the RF-only intelligent channel modeling and finally lands on MMICM. Then, we have elaborated and investigated recent advances in the topic of capturing typical channel characteristics and features, i.e., channel non-stationarity and consistency, via convention

关键词： communication channels (information theory)

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Channel Estimation for Holographic communications in Hybrid Near-Far Field

Channel Estimation for Holographic Communications in Hybrid ...

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IEEE Conference on Global communications (GLOBECOM)

作者： Shaohua Yue Shuhao Zeng Liang Liu Boya Di State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Peking University Beijing China The Hong Kong Polytechnic University Hong Kong SAR China

To realize holographic communications, a potential technology for spectrum efficiency improvement in the future sixth-generation (6G) network, antenna arrays inlaid with numerous antenna elements will be deployed. However, the increase in antenna aperture size makes some users lie in the Fresnel region, leading to the hybrid near-field and far-field communication mode, where the conventional far-field channel estimation methods no longer work well. To tackle the above challenge, this paper considers channel estimation in a hybrid-field multipath environment, where each user and each scatterer can be in either the far-field or the near-field region. First, a joint angular-polar domain channel transform is designed to capture the hybrid-field channel's near-field and far-field features. We then analyze the power diffusion effect in the hybrid-field channel, which indicates that the power corresponding to one near-field (far-field) path component of the multipath channel may spread to far-field (near-field) paths and causes estimation error. We design a novel power-diffusion-based orthogonal matching pursuit channel estimation algorithm (PD-OMP). It can eliminate the prior knowledge requirement of path numbers in the far field and near field, which is a must in other OMP-based channel estimation algorithms. Simulation results show that PD-OMP outperforms current hybrid-field channel estimation methods.

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Broadband and lossless lithium niobate valley photonic crystal waveguide [Invited]

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Chinese Optics Letters 2021年第6期19卷 72-75页

作者： Rui Ge Xiongshuo Yan Yuping Chen Xianfeng Chen State Key Laboratory of Advanced Optical Communication Systems and Networks School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China

We investigate the influences of structure parameters and interface shapes on the bandwidth of the edge state of lithium niobate valley photonic crystals. By increasing the size difference of two air holes in the same unit cell, we find that the bandwidth of the lossless nontrivial edge state possesses a peak value of 0.0201(a/λ), which can be used to construct broadband valley photonic crystal waveguides. Mode field distributions verify that the waveguide is robust against sharp bends and exhibits chirality. When the unit cell is arranged in a bearded interface with the top and bottom components showing negative and positive valley Chern numbers, respectively, we find that the lithium niobate valley photonic crystal is more likely to exhibit a lossless edge state, which is difficult to be realized in valley waveguides with low refractive index materials. This work can provide guidance on the design of the high-performance topological waveguide.

关键词： lithium niobate valley photonic crystal waveguide propagation loss

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Inherent Residual optical Carrier Assisted Phase Retrieval Receiver Using Low-Cost Finite Extinction Ratio IQ Modulator Down to 10 dB

Inherent Residual Optical Carrier Assisted Phase Retrieval R...

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OptoElectronics and communications Conference, OECC

作者： Xiaobo Zeng Yixiao Zhu Yicheng Xu Qunbi Zhuge Weisheng Hu School of Automatic and Electronic Information Hunan Key Laboratory of Credible Intelligent Navigation and Positioning (CINP) Xiangtan University Xiangtan China Department of Electronic Engineering State Key Laboratory of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University Shanghai China

ISBN: (数字)9798350308396

ISBN: (纸本)9798350308402

An inherent residual optical carrier-based phase retrieval receiver using finite extinction ratio (ER) IQ modulator is proposed, eliminating pilot-symbols or pilot tones of conventional counterparts. The cooperation of polynomial digital predistortion and proposed offset correction obtains 0.89 dB Global-SNR gain, alleviating the ERs of IQ-modulator down to 10 dB.

关键词： Radio frequency Phase modulation optical device fabrication Extinction ratio optical receivers Adaptive optics Predistortion Polynomials optical modulation Gain

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Calibration of Fiber-Optic Time Synchronization system Over 800km

Calibration of Fiber-Optic Time Synchronization System Over ...

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IEEE International Frequency Control Symposium

作者： Jiameng Dong Zhaohui Wang Rui Zhang Song Yu Bin Luo Hong Guo State Key Laboratory of Information Photonics and Optical Communications School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing China State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics and Center for Quantum Information Technology Peking University Beijing China

SummaryDue to the excellent performance in accuracy and stability, fiber-optic time synchronization is becoming a key technology in the field of time-frequency metrology. And the accuracy of fiber-optic time synchronization system mainly depends on asymmetry calibration. Here we study the calibration of time synchronization system over 800km laboratory fiber link. Asymmetry caused by chromatic dispersion, bidirectional EDFAs, sending and receiving devices are investigated. After calibration, the residual of clock difference between two sites is 56.80ps, and the timing jitter is 33.91ps. By further optimizing the whole system and the method of calibration, a system with accuracy better than 50ps over thousands of kilometers fiber link is expected to be obtained in the future.

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