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Asia Communications and Photonics Conference and Exhibition (ACP)

作者： Liang Xin Ning Ma Tianli Hui Wenjing Song Shuchao Wang Yujun Bai Haiqing Lv Wen Wang Feng Yan Xiaojun Tang Yuanbo Zhai Tigang Ning Beijing Satellite Manufacturing Co. Ltd Beijing China Key Laboratory of All Optical Network & Advanced Telecommunication Network of EMC Beijing Jiaotong University Beijing China

A method for measuring the thermal expansion coefficient (CTE) of carbon fiber composites based on Fabry-Pérot (FP) cavity is proposed. The CTE of a carbon fiber composite is measured to be $5.18\times 10^{-6}/ {... 详细信息

ISBN: (数字)9798350379266

ISBN: (纸本)9798350379273

关键词： Temperature measurement Temperature sensors Thermal expansion Surface waves Wavelength measurement Thermal conductivity optical fiber communication Carbon optical fiber testing Photonics

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Metalens polarization beam splitter based on fiber end face 13

Metalens polarization beam splitter based on fiber end face

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13th International Conference on Information Optics and Photonics, CIOP 2022

作者： Huang, Jing Ruan, Zuliang Zheng, Jingjing Pei, Li Ning, Tigang Li, Jing Wang, Jianshuai Bai, Bing Institute of Lightwave Technology School of Electronic and Information Engineering Beijing Jiaotong University Beijing100044 China Key Laboratory of All Optical Network & Advanced Telecommunication Network of EMC Beijing Jiaotong University Beijing100044 China

ISBN: (纸本)9781510660632

Polarization beam splitter is an important part of integrated optical system to overcome the strong polarization dependence of silicon nanodevices, and has broad application prospects in optical fiber communication and polarization imaging. In this paper, a polarization beam splitter of metalens based on the fiber end face is designed. Through the planar light field control ability of metalens and the coordinated regulation of the geometric phase and propagation phase, the device adjusts the medium duty cycle in the meta-unit and the rotation angle of the nanoantenna to realize the polarization beam splitting and focusing simultaneously. In order to simplify the manufacturing process and achieve high focusing efficiency even further, Si with high transmittance in the near infrared band is selected as the nanoantenna, and SiO2 is used as the substrate. Since the substrate used the same material with fiber cladding, compared with the traditional polarization beam splitter, the structure can directly etch the nanofins periodically on the fiber end face, which is convenient for optical system integration. Theoretical design and numerical simulation results show that any polarized light in fiber cladding can realize polarization focusing through fiber end face. © 2022 SPIE.

关键词： Polarization

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A deep learning-enhanced multimode fiber Bragg grating (MMFBG) bidirectional bending sensor

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IEEE Sensors Journal 2025年第12期25卷 21674-21682页

作者： Xu, Jing Liu, Yan Hou, Zhibo Pang, Lezhi Li, Guangde Xu, Hang Ren, Wenhua Wang, Muguang Yan, Fengping Beijing Jiaotong University Key Lab of All Optical Network and Advanced Telecommunication Network of Ministry of Education Institute of Lightwave Technology Beijing100044 China Beijing Jiaotong University School of Electronic and Information Engineering Beijing100044 China

In this research, a deep learning-enhanced multimode fiber Bragg grating (MMFBG) bending sensor is proposed with the capability of bidirectional bending sensing. Unlike fiber Bragg gratings (FBGs) in singlemode fibers (SMFs), MMFBGs exhibit multiple reflected peaks in their reflected spectra, especially when coreoffset launching is employed. When various bending is applied to the grating, the couplings between the forward and backward fundamental mode and higher order modes are affected, which results in a changed reflected spectrum. Therefore, the reflected spectrum with rich information can be used to characterize the bending. The MMFBG is encapsulated using a silicone tube filled with polydimethylsiloxane (PDMS) to protect the grating and enhance the sensor’s stability. In order to track the nonlinear relationship between the spectrum and the bending of the MMFBG, a deep learning model is utilized integrating a one-dimensional convolutional neural network (1D-CNN), a bidirectional long short-term memory (BiLSTM) network, and a self-attention mechanism, which enables accurate prediction of bidirectional bending angles. The experimental results demonstrate that within the bending range from -135° to 135°, the proposed model achieves a coefficient of determination (R2) of 0.9999 and a root mean square error (RMSE) of 0.8022° in bending prediction. For unknown bending angles, the RMSE is 4.0094°. Compared to traditional wavelength monitoring and deep learning based methods, the proposed sensing scheme enables a more efficient and accurate sensing of bidirectional bending with a very simple structure. © 2001-2012 IEEE.

关键词： Deep neural networks

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A Cluster-Based Statistical Channel Model for Integrated Sensing and Communication Channels

arXiv

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arXiv 2024年

作者： Zhang, Zhengyu He, Ruisi Ai, Bo Yang, Mi Niu, Yong Zhong, Zhangdui Li, Yujian Zhang, Xuejian Li, Jing The State Key Laboratory of Advanced Rail Autonomous Operation Beijing Jiaotong University Beijing100044 China The Key Laboratory of All Optical Network and Advanced Telecommunication Network of EMC Institute of Lightwave Technology Beijing Jiaotong University Beijing100044 China

The emerging 6G network envisions integrated sensing and communication (ISAC) as a promising solution to meet growing demand for native perception ability. To optimize and evaluate ISAC systems and techniques, it is crucial to have an accurate and realistic wireless channel model. However, some important features of ISAC channels have not been well characterized, for example, most existing ISAC channel models consider communication channels and sensing channels independently, whereas ignoring correlation under the consistent environment. Moreover, sensing channels have not been well modeled in the existing standard-level channel models. Therefore, in order to better model ISAC channel, a cluster-based statistical channel model is proposed in this paper, which is based on measurements conducted at 28 GHz. In the proposed model, a new framework based on 3GPP standard is proposed, which includes communication clusters and sensing clusters. Clustering and tracking algorithms are used to extract and analyze ISAC channel characteristics. Furthermore, some special sensing cluster structures such as shared sensing cluster, newborn sensing cluster, etc., are defined to model correlation and difference between communication and sensing channels. Finally, accuracy of the proposed model is validated based on measurements and simulations. Copyright © 2024, The Authors. all rights reserved.

关键词： Clustering algorithms

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Amplification characteristics in active tapered segmented cladding fiber with large mode area

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High Power Laser Science and Engineering 2021年第2期9卷 247-256页

作者： Caijian Xie Tigang Ning Jingjing Zheng Li Pei Jianshuai Wang Jing Li Haidong You Chuangye Wang Xuekai Gao Key Laboratory of All Optical Network&Advanced Telecommunication Network of EMC Institute of Lightwave TechnologyBeijing Jiaotong UniversityBeijing 100044China Science and Information College Qingdao Agricultural UniversityQingdao 266109China

A kind of tapered segmented cladding fiber(T-SCF)with large mode area(LMA)is proposed,and the mode and amplification characteristics of T-SCFs with concave,linear,and convex tapered structures are investigated based on finite-element method(FEM)and few-mode steady-state rate *** results indicate that the concave tapered structure can introduce high loss for high-order modes(HOMs)that is advantageous to achieve single-mode operation,whereas the convex tapered structure provides large effective mode area that can help to mitigate nonlinear ***,the small-to-large amplification scheme shows further advantages on stripping off HOMs,and the large-to-small amplification scheme decreases the heat load density induced by the high-power ***,singlemode propagation performance,effective mode area,and heat load density of the T-SCF are superior to those of tapered step index fiber(T-SIF).These theoretical model and numerical results can provide instructive suggestions for designing high-power fiber lasers and amplifiers.

关键词： bending loss heat load density high-order modes filtering large mode area tapered fibers

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Terahertz Multidimensional-Multiplexing and Refractive-Index-Sensing Integrated Device Based On Subwavelength Birefringent Fibers

SSRN

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SSRN 2023年

作者： Jie, Lu Li, Haisu Liu, Yajing Wang, Jianshuai Atakaramians, Shaghik Ren, Guobin Pei, Li Key Laboratory of All Optical Network and Advanced Telecommunication Network of EMC Institute of Lightwave Technology Beijing Jiaotong University Beijing100044 China School of Electrical Engineering and Telecommunications UNSW Sydney NSW2052 Australia

To meet the urgent demand of transmission capacity enhancement in the context of next-generation communication systems, terahertz wave has been one of key technologies thanks to its wider bandwidth in comparison to current microwave. Multidimensional multiplexing methods can further increase both spectral and channel efficiencies to enhance system capacity. In addition, the next-generation smart network architecture requires not only high-speed communications, also environmental sensing abilities. Here, we propose a polarization-maintaining subwavelength fiber based multidimensional multiplexing and sensing integrated device, consisting of directional couplers, a Y-splitter and Bragg gratings. Such device features integrated functionalities including polarization- and frequency-(de)multiplexing, dispersion compensation, as well as refractive-index sensing. For demultiplexing, the x-polarized signal is dropped using a directional coupler, followed by dispersion compensation utilizing a uniform grating. For multiplexing, an additional frequency carrier can be added to the transmission channel from the orthogonal direction assisted by a frequency-dependent coupler. Furthermore, a π-shifted grating is integrated to monitor the environmental refractive-index variations. The proposed fiber-integrated device may pave a new avenue towards high-speed communications along with environmental sensing for the next-generation information systems. © 2023, The Authors. all rights reserved.

关键词： Fibers

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Tunable frequency-multiplying optoelectronic oscillator based on a dual-parallel Mach-Zehnder modulator incorporating a phase-shifted fiber Bragg grating

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Optoelectronics Letters 2020年第6期16卷 405-409页

作者： ZHANG Yao NING Ti-gang LI Jing ZHENG Jing-jing LIU Ling DONG Xiao-wei PEI Li Key Lab of All Optical Network&Advanced Telecommunication Network of EMC Institute of Lightwave TechnologyBeijing Jiaotong UniversityBeijing 100044China College of Information Engineering North China University of TechnologyBeijing 100144China

A tunable frequency-multiplying optoelectronic oscillator(OEO) based on a dual-parallel Mach-Zehnder modulator(DPMZM) is proposed and experimentally demonstrated. In the proposed system, the tunable fundamental microware signal is generated by a tunable optoelectronic oscillator incorporating a phase-shifted fiber Bragg grating(PS-FBG). By adjusting the DC bias of the DPMZM, the frequency-doubled microwave signal with a tunable frequency range from 11 GHz to 20 GHz and the frequency-quadrupled microwave signal with a tunable frequency range from 22.5 GHz to 26 GHz are generated. The phase noises of the fundamental, frequency-doubled and frequency-quadrupled signals at 10 k Hz offset frequency are-105.9 d Bc/Hz,-103.3 d Bc/Hz and-86.2 d Bc/Hz, respectively.

关键词： MZM FBG Tunable frequency-multiplying optoelectronic oscillator based on a dual-parallel Mach-Zehnder modulator incorporating a phase-shifted fiber Bragg grating Bragg

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Dynamic V2V Channel Measurement and Modeling at Street Intersection Scenarios

Dynamic V2V Channel Measurement and Modeling at Street Inter...

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作者： Yang, Mi Ai, Bo He, Ruisi Ma, Zhangfeng Mi, Hang Fei, Dan Zhong, Zhangdui Li, Yujian Li, Jing Beijing Jiaotong University State Key Laboratory of Rail Traffic Control and Safety Collaborative Innovation Center of Railway Traffic Safety Beijing100044 China Beijing Jiaotong University State Key Laboratory of Rail Traffic Control and Safety Beijing100044 China Peng Cheng Laboratory Shenzhen518055 China Shaoyang University College of Information Engineering Shaoyang422000 China Institute of Lightwave Technology Beijing Jiaotong University Key Laboratory of All Optical Network and Advanced Telecommunication Network of Emc Beijing100044 China

Vehicular communication has been widely concerned by academia and industry. Wireless channel characterization and modeling are the foundation of communication systems. Compared with typical road scenarios such as urban and suburban areas, wireless channel characterization in intersections is a challenging task. In this article, channel measurements at 5.9 GHz in street intersection scenarios are carried out and provide data for the characterization and modeling of time-varying vehicular channels. This article proposes a double-slope path loss model, which can accurately reflect the signal propagation loss at intersections. Furthermore, the time-varying spatial characteristics of multipath are extracted and analyzed, and the azimuth and elevation spread of arrival are statistically characterized. The influence of obstacles on multipath spatial characteristics in intersection scenarios is investigated. Then, we investigate the spatial stationarity of channels and analyze the possible reasons for the differences in spatial stationarity of different scenarios. In addition, based on multipath extraction, we quantitatively analyze the energy of dense multipath components in different propagation scenarios. The research in this article can enrich the investigation of vehicular channels and enable the analysis and design of vehicular communication systems. © 1963-2012 IEEE.

关键词： Vehicle to vehicle communications

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Simulation Analysis of Balance Detection Technique in Coherent optical Receiver

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Optics and Photonics Journal 2021年第8期11卷 301-313页

作者： Piaokun Zhang Zhongwei Tan Zhichao Ding Lijun Guo Key Laboratory of All Optical Network & Advanced Telecommunication Network of EMC Institute of Lightwave Technology Beijing Jiaotong University Beijing China

This paper introduces the working principle of the balanced heterodyne detection system, establishes the corresponding mathematical model, deduces the signal to noise ratio (SNR) formula of the balanced heterodyne detection. By comparing balance heterodyne detection with general coherent detection with MATlab numerical simulation, the superiority of balance heterodyne detection system is proved theoretically. Finally, the simulation models of ordinary heterodyne detection, balance detection and double balance detection system are built by OptiSystem. The simulation results are consistent with the conclusions derived from the mathematical analysis, which provides a new method for the research of weak laser detection technology.

关键词： Balance Heterodyne Detection 90? optical Mixer Signal to Noise Ratio The Numerical Simulation

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Calculation of the Coupling Coefficient of Twin-Core Fiber Based on the Supermode Theory with Finite Element Method

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Optics and Photonics Journal 2021年第8期11卷 402-411页

作者： Tianhao Zhao Wenhua Ren Tingya Yin Fan Wang Key Laboratory of All Optical Network & Advanced Telecommunication Network of EMC Institute of Lightwave Technology Beijing Jiaotong University Beijing China

Currently, coupled mode theory (CMT) is widely used for calculating the coupling coefficient of twin-core fibers (TCFs) that are used in a broad range of important applications. This approach is highly accurate for scenarios with weak coupling between the cores but shows significant errors in the strong coupling scenarios, necessitating the use of a more accurate method for coupling coefficient calculations. Therefore, in this work, we calculate the coupling coefficients of TCFs using the supermode theory with finite element method (FEM) that has higher accuracy than CMT, particularly for the strong coupling TCF. To investigate the origin of the differences between the results obtained by these two methods, the modal field distributions of the supermodes of TCF are simulated and analyzed in detail.

关键词： Coupling Coefficient Twin-Core Fiber Supermode Theory Finite Element Method Coupled Mode Theory

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