检索结果-内蒙古大学图书馆

Ultranarrow Bandwidth optical Filter Based on Laser Cooled 87Rb Atoms

学校读者我要写书评

暂无评论

Ultranarrow Bandwidth Optical Filter Based on Laser Cooled 8...

IEEE International Frequency Control Symposium

作者： Xiaolei Guan Wei Zhuang Tiantian Shi Jianxiang Miao Jia Zhang Jingbiao Chen Bin Luo State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Peking University Beijing China State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Beijing China National Institute of Metrology Beijing China

We propose and implement two ultranarrow-bandwidth optical filters with different principles based on laser-cooled 87 Rb atoms. Using the cold atomic cloud trapped in magneto-optical trap (MOT) to replace the vapor cell of traditional Faraday anomalous dispersion optical filter (FADOF), the effect of Doppler broadening on the transmitted bandwidth of FADOF will be effectively suppressed to the order of natural linewidth. Thus, an ultranarrow-bandwidth FADOF with a bandwidth of 2.7(2) MHz and a peak transmission of 3.2% is realized. It is the narrowest bandwidth FADOF known at present. Moreover, a transmission-enhancing method based on optical pumping is proposed. The two circularly polarized components of a linearly polarized probe laser have a large refractive index difference (induced dichroism), when it goes through the unidirectional population of atoms. Thus, forming a large rotation angle with high transmission. The two schemes can be extended to almost all kinds of atomic optical filters and may find applications in active optical frequency standard and self-stabilizing laser.

关键词：

Delta-Sigma Modulation with Coherent Detection for High-Fidelity 4194304-QAM Transmission at 71.5dB SNR

学校读者我要写书评

暂无评论

Delta-Sigma Modulation with Coherent Detection for High-Fide...

Asia communications and Photonics Conference and Exhibition (ACP)

作者： Yixiao Zhu Xiansong Fang Longjie Yin Lei Zhang Fan Zhang Weisheng Hu State Key Laboratory of Advanced Optical Communication System and Networks Shanghai Jiao Tong University Shanghai China State Key Laboratory of Advanced Optical Communication System and Networks Peking University Beijing China

We experimentally demonstrate 1/2-bit delta-sigma modulation and transmission in a 40Gbaud QPSK/16-QAM coherent system. After 24km SSMF transmission, up to 2.5Gbaud 4194304-QAM Nyquist signal is successfully transmitt... 详细信息

ISBN: (纸本)9781957171005

关键词： Baseband Asia Coherence Delta-sigma modulation Tuning Signal to noise ratio Photonics

Synesthesia of Machines (SoM)-Enhanced ISAC Precoding for Vehicular networks with Double Dynamics

学校读者我要写书评

暂无评论

IEEE Transactions on communications 2025年

作者： Yang, Zonghui Gao, Shijian Cheng, Xiang Yang, Liuqing Peking University State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Beijing100871 China Internet of Things Thrust Guangzhou511400 China Hong Kong University of Science and Technology Department of Electronic and Computer Engineering Hong Kong

Integrated sensing and communication (ISAC) technology is vital for vehicular networks, yet the time-varying communication channels and rapid movement of targets present significant challenges for real-time precoding design. Traditional optimization-based methods are computationally complex and strongly depend on perfect prior information, which is often unavailable in double-dynamic scenarios. In this paper, we propose a synesthesia of machine (SoM)-enhanced precoding paradigm that leverages modalities such as positioning and initial channel information to adapt to these dynamics. Utilizing a deep reinforcement learning (DRL) framework, our approach pushes ISAC performance boundaries. We also introduce a parameter-shared actor-critic architecture to accelerate training in complex state and action spaces. Extensive experiments validate the superiority of our method over existing approaches. © 1972-2012 IEEE.

关键词： Deep reinforcement learning

High-Fidelity and Low-Latency Hollow-Core NANF Transmission at 2-μm Band with 112-Gbps/lambda Data-Rate and 850-m Long Distance

学校读者我要写书评

暂无评论

High-Fidelity and Low-Latency Hollow-Core NANF Transmission ...

International Conference on optical communications and networks (ICOCN)

作者： Xuelin Zhang Lei Shen Jiangbing Du Jiacheng Liu Peng Li Lei Zhang Jie Luo Zuyuan He State Key Laboratory of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University 800 Dongchuan Road Minhang Shanghai China State Key Laboratory of Optical Fiber and Cable Manufacture Technology YOFC Wuhan China Optics Valley Laboratory Wuhan China

The 2-μm-band hollow-core NANF transmission is demonstrated with the longest transmission distance of 850m at 56 Gbps and 100m at the highest Intensity-Modulation-Direct-Detection (IMDD) data rate of 112 Gbps by Disc...

关键词：

Task-oriented Over-the-Air Computation for Edge-device Co-inference with Balanced Classification Accuracy

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Jiao, Xiang Wen, Dingzhu Zhu, Guangxu Jiang, Wei Luo, Wu Shi, Yuanming State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Peking University Beijing China Shenzhen Research Institute of Big Data Shenzhen China Dingzhu Wen and Yuanming Shi are with Network Intelligence Center School of Information Science and Technology ShanghaiTech University Shanghai China Shenzhen Research Institute of Big Data Shenzhen China The State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Peking University Beijing China

Edge-device co-inference, which concerns the cooperation between edge devices and an edge server for completing inference tasks over wireless networks, has been a promising technique for enabling various kinds of intelligent services at the network edge, e.g., auto-driving. In this paradigm, the concerned design objective of the network shifts from the traditional communication throughput to the effective and efficient execution of the inference task underpinned by the network, measured by, e.g., the inference accuracy and latency. In this paper, a task-oriented over-the-air computation scheme is proposed for a multi-device artificial intelligence system. Particularly, a novel tractable inference accuracy metric is proposed for classification tasks, which is called minimum pair-wise discriminant gain. Unlike prior work measuring the average of all class pairs in feature space, it measures the minimum distance of all class pairs. By maximizing the minimum pair-wise discriminant gain instead of its average counterpart, any pair of classes can be better separated in the feature space, and thus leading to a balanced and improved inference accuracy for all classes. Besides, this paper jointly optimizes the minimum discriminant gain of all feature elements instead of separately maximizing that of each element in the existing designs. As a result, the transmit power can be adaptively allocated to the feature elements according to their different contributions to the inference accuracy, opening an extra degree of freedom to improve inference performance. Extensive experiments are conducted using a concrete use case of human motion recognition to verify the superiority of the proposed design over the benchmarking scheme. Copyright © 2024, The Authors. All rights reserved.

关键词： Degrees of freedom (mechanics)

Silicon non-blocking 4×4 optical switch with automated polarization adjustment

学校读者我要写书评

暂无评论

Chinese Optics Letters 2021年第10期19卷 38-43页

作者： Xiaorui Li Liangjun Lu Wei Gao Xin Li Jianping Chen Linjie Zhou State Key Laboratory of Advanced Optical Communication Systems and Networks ShanghaMnstitute for Advanced Communication and Data ScienceShanghai Key Laboratory of Navigation and Location ServicesDepartment of Electronic EngineeringShanghai Jiao Tong UniversityShanghai 200240China

We demonstrate a polarization-insensitive silicon 4×4 optical switch based on Mach–Zehnder interferometer(MZI)switch ***-chip polarization controllers are integrated before the switch fabric to automatically adjust an arbitrary input polarization to the transverse electric *** 4×4 switch fabric is based on a dilated double-layer network architecture to completely cancel the first-order ***-optic phase shifters are integrated in the MZI switch elements and the polarization controllers for adjustment of the switching state and polarization,*** develop a polarization control algorithm based on a gradient descent method for automated polarization *** polarization recovery time is less than 4 ms,and the measured polarization-dependent loss is~2 d *** scheme provides a new solution for realizing polarization-insensitive silicon optical switches.

关键词： optical switch polarization control silicon photonics optical routing

Arbitrary control of the flow of light using pseudomagnetic fields in photonic crystals at telecommunication wavelengths

学校读者我要写书评

暂无评论

arXiv 2025年

作者： Hu, Pan Sun, Lu Chen, Ce Li, Jingchi Ni, Xiong He, Xintao Dong, Jianwen Su, Yikai State Key Lab of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University Shanghai200240 China State Key Laboratory of Optoelectronic Materials and Technologies School of Physics Sun Yat-Sen University Guangzhou510275 China

In photonics, the idea of controlling light in a similar way that magnetic fields control electrons has always been attractive. It can be realized by synthesizing pseudomagnetic fields (PMFs) in photonic crystals (PhCs). Previous works mainly focus on the Landau levels and the robust transport of the chiral states. More versatile control over light using complex nonuniform PMFs such as the flexible splitting and routing of light has been elusive, which hinders their application in practical photonic integrated circuits. Here we propose an universal and systematic methodology to design nonuniform PMFs and arbitrarily control the flow of light in silicon PhCs at telecommunication wavelengths. As proofs of concept, a low-loss S-bend and a highly efficient 50:50 power splitter based on PMFs are experimentally demonstrated. A high-speed data transmission experiment is performed on these devices to prove their applicability in real communication systems. The proposed method offers a new paradigm for the exploration of fundamental physics and the development of novel nanophotonic devices. Copyright © 2025, The Authors. All rights reserved.

关键词： Photonic integrated circuits

Identity information based on human magnetocardiography signals

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Zhang, Pengju Sun, Chenxi Zhang, Jianwei Guo, Hong State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Center for Quantum Information Technology Peking University Beijing100871 China School of Physics Peking University Beijing100871 China

We have developed an individual identification system based on magnetocardiography (MCG) signals captured using optically pumped magnetometers (OPMs). Our system utilizes pattern recognition to analyze the signals obtained at different positions on the body, by scanning the matrices composed of MCG signals with a 2 × 2 window. In order to make use of the spatial information of MCG signals, we transform the signals from adjacent small areas into four channels of a dataset. We further transform the data into time-frequency matrices using wavelet transforms and employ a convolutional neural network (CNN) for classification. As a result, our system achieves an accuracy rate of 97.04% in identifying individuals. This finding indicates that the MCG signal holds potential for use in individual identification systems, offering a valuable tool for personalized healthcare management. © 2024, CC BY.

关键词： Magnetocardiography

Long distance local local oscillator continuous variable quantum key distribution with digital signal processing

学校读者我要写书评

暂无评论

arXiv 2025年

作者： Qi, Dengke Wang, Xiangyu Ma, Jiayu Li, Zhenghua Chen, Ziyang Lu, Yueming Yu, Song State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Beijing100876 China School of Cyberspace Security Beijing University of Posts and Telecommunications Beijing100876 China State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Center for Quantum Information Technology Peking University Beijing100871 China

Quantum key distribution relying on the principles of quantum mechanics enables two parties to produce a shared random secret key, thereby ensuring the security of data transmission. Continuous variable quantum key distribution (CV-QKD) is widely applied because it can be well combined with standard telecommunication technology. Compared to CV-QKD with a transmitting local oscillator, the proposal of CV-QKD with a local local oscillator overcomes the limitation that local oscillator will attenuate as transmission distance increases, providing new possibilities in long-distance transmission. However, challenges still persist in practical long-distance transmission, including data sampling and recovery under low signal-to-noise ratio conditions. In order to better recover data and reduce the additional excess noise, we propose the least squares fitting algorithm to get more accurate sampling data and complete more accurate phase compensation. Herein, we demonstrate the long-distance local local oscillator CV-QKD experiment which have considered the effect of finite-size block over 120 km of standard optical fiber with high efficient real-time post-processing. The results not only verify the good performance of the system over long distance, but also paves the way for large-scale quantum secure communications in the future. Copyright © 2025, The Authors. All rights reserved.

关键词： Quantum cryptography