Article
Optics
Yinghao Guo, Yudan Cheng, Youchao Jiang, Min Cao, Min Tang, Wenhua Ren, Guobin Ren
Summary: In this study, an artificial neural network-based machine learning method is proposed for the inverse design of flattop (FT) beam fiber. The trained network accurately predicts the structural parameters and performance of FT beam, providing efficient and accurate results.
OPTICS COMMUNICATIONS
(2022)
Article
Physics, Applied
Renxuan Liu, Wei Juan, Heng Yang, Zhouyi Hu, Jiarui Li, Jun Hu
Summary: This paper investigates the theoretical model of the coupling efficiency of BG beams to FMFs under perfect alignment, lateral or vertical offsets, and random angular jitter, and compares it with SMFs. FMFs have a higher coupling efficiency and flatter response characteristics to deviations from ideal conditions compared to SMFs under the same conditions. The effects of the half-cone angle and topological charge of the BG beam on the coupling efficiency and response characteristics during nonideal conditions are also studied. Adjusting the half-cone angle, topological charge, and focal length can lead to a higher coupling efficiency, making them a more practical choice for information transmissions such as mobile platform communication and the transmission of pedestrian data collected during transportation. The research results could aid in the application of BG beams and other OAM beams coupled with FMFs.
MODERN PHYSICS LETTERS B
(2023)
Article
Optics
Xiao Liu, Meiling Zhang, Guijun Hu
Summary: In this paper, a parallel integrated few-mode fiber Bragg grating (FM-FBG) with high-order mode self-coupling reflection is produced using the femtosecond laser point-by-point method. The effects of various parameters on the self-coupling reflectivity of different modes are investigated. The experimental results show that the self-coupling reflectivity of the four modes at the wavelength of 1550 nm differs.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Yaping Liu, Zhiqun Yang, Xutao Wang, Yongmin Jung, Lin Zhang
Summary: This paper proposes a new design for few-mode erbium-doped fiber amplifiers (FM-EDFAs) that achieves significantly reduced differential modal gain (DMG) through strong mode coupling. A new numerical model based on a fiber transfer matrix is used to systematically investigate the DMGs of FM-EDFAs and analyze two different types of six-mode fiber amplifiers as exemplar demonstrations.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Electrical & Electronic
Kunimasa Saitoh
Summary: This paper describes the coupling mechanisms and design issues in multi-core fibers (MCFs) for space division multiplexing. For uncoupled MCFs, a design procedure considering random structural perturbations, correlation length, and birefringence beat length on inter-core crosstalk is presented based on coupled mode theory. Furthermore, for coupled MCFs, a numerical estimation method for modal dispersion is described, along with a method to enhance random mode mixing.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Optics
Junbo Zhu, Haiyang Huang, Yingxuan Zhao, Yang Li, Zhen Sheng, Fuwan Gan
Summary: We have designed a silicon-based four-mode edge coupler that can efficiently couple multimode silicon waveguides and few-mode fibers through mode conversion and power splitting. This structure is compact, low loss, and fabrication-tolerant.
CHINESE OPTICS LETTERS
(2022)
Article
Engineering, Multidisciplinary
Weisheng Zhang, Yue Wang, Sung-Kie Youn, Xu Guo
Summary: This study proposes a sketch-guided topology optimization approach based on machine learning, which incorporates computer sketches as constraint functions to improve the efficiency of computer-aided structural design models and meet the design intention and requirements of designers.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2024)
Article
Engineering, Environmental
Kalagotla Sai Chandana, Swetha Karka, Manleen Kaur Gujral, Reddi Kamesh, Anirban Roy
Summary: In recent years, there has been an increased interest in utilizing CO2 for the production of different chemicals due to concerns about global warming. This study focuses on developing a machine learning framework for the modeling and design of catalysts that can directly convert CO2 to lower olefins (LO). Through comprehensive review and data mining, a database was formed from 55 relevant reports, with 18 input parameters and catalyst activity (CO2 conversion (%) and LO selectivity (%)) as the output parameter. Artificial neural network models were developed using Bayesian-Regularisation (BR) and Levenberg-Marquardt (LM) backpropagation learning algorithms to predict catalyst activity. The performance of these models was compared to linear, tree-based, and kernel-based ML models, and evaluated based on statistical measures. The ANN-BR model showed the least deviation from experimental data in predicting CO2 conversion and LO selectivity, with R=0.90 and 0.8, RMSE=8.43 and 16.73, AAD=5.8 and 9.5 for test data respectively, compared to other ML models. The importance of predominant features affecting the target variables was analyzed through input contribution. Furthermore, integrated catalyst and process design using inverse design based on multi-objective optimization (NSGA-II) with the ANN-BR as the objective function led to a two-to-three-fold increase in yields, with optimal catalyst composition, operating conditions, and novel combinations of catalysts for efficient conversion of CO2 to LO, compared to reported experimental results.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Engineering, Electrical & Electronic
Xingjie Fan, Dawei Wang, Julian Cheng, Jingkai Yang, Jing Ma
Summary: Few-mode fiber plays a significant role in free-space optical communication, outperforming single-mode fiber, especially in high signal-to-noise ratio scenarios.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Optics
Tongxin Yang, Hu Zhang, Lixia Xi, Qiankun Li, Xiaoguang Zhang, Xiaoqian Wang, Wenbo Zhang, Xianfeng Tang
Summary: This paper presents a novel polarization-maintaining few-mode fiber with an elliptical core and hole-assisted structure. By introducing geometry asymmetry, the fiber breaks the degeneracy of modes and supports multiple polarization maintaining modes. The optimized fiber exhibits excellent propagation properties, making it suitable for mode division multiplexing systems to improve channel utilization.
OPTICS COMMUNICATIONS
(2022)
Article
Optics
Jing Li, Mingchao Wang, Han Ye
Summary: In this paper, a heuristic inverse design scheme for TE-polarized mode conversions in silicon waveguides is presented. No additional complicated structures are added to the waveguide. The optimal design of the boundary deformations of the functional region is determined using the gradient-based method of moving asymptotes. The proposed mode converters show high mode purity and transmission efficiency.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Optics
Bhagyalaxmi Behera, Shailendra Kumar Varshney, Mihir Narayan Mohanty
Summary: This work presents a new fiber design that can support ten modes with large mode separation and low optical loss in the C-band. The fiber design optimizes the chromatic dispersion parameter and bending loss and meets the ITU-G.655 standard.
Article
Chemistry, Analytical
Jianxun Yu, Fengze Tan, Changyuan Yu
Summary: With the widespread use of few-mode fibers, the testing of mode characteristics has become crucial. This paper discusses the current testing techniques for few-mode fibers and selects and demonstrates the principle of the S-2 imaging technique for few-mode fiber characterization. A few-mode fiber characterization system based on the S-2 imaging technique is built to accurately measure the mode dispersion of two-mode fibers of different lengths. Various filters are then applied to extract the fundamental and high-order modes and obtain mode coupling components. The proposed system spatially characterizes the few-mode fiber by resolving the interference information from the superimposed optical field and offers a simple structure and easy operation, providing parameter guidance for designing and optimizing few-mode fibers in sensing experiments.
Article
Optics
Shuang Wang, Xiao Liu, Haiyan Wang, Guijun Hu
Summary: We propose and experimentally demonstrate a high-order mode fiber laser based on few-mode fiber gratings. The laser can achieve simultaneous lasing of different modes at the same wavelength and different modes at different wavelengths, making it suitable for mode-division multiplexing-wavelength-division multiplexing optical communication systems.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Optics
Baorui Yan, Jianyong Zhang, Muguang Wang, Youchao Jiang, Shuchao Mi
Summary: In this paper, a deep learning method is proposed to fully characterize the degenerated mode of high-order mode (HOM) group in few-mode fibers (FMFs). The method uses three polarization projection images to recover the modal coefficients and utilizes a well-trained deep convolutional neural network (CNN) to efficiently learn the mapping relationship between the two-dimensional intensity distribution and the one-dimensional coefficients space of eigenmodes. The evaluation results show the feasibility and stability of the proposed method based on the coefficient errors and image correlation.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
He Li, Qingwen Liu, Yanming Chang, Yimin Luo, Jinbo Qiu, Zuyuan He
Summary: In this work, the influence of vibration induced beat frequency shift in optical frequency domain reflectometry (OFDR) is analyzed and assessed. An adaptive two-dimensional cross-correlation algorithm is proposed for beat frequency shift compensation, which achieves precise strain demodulation. Experimental results demonstrate a suppression of crosstalk power spectral density (PSD) up to 40.5 dB using the proposed algorithm.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Lulu Wang, Chengkun Cai, Jiaxiong LI, Wei Zhou, Long Zhu, Andong Wang, Jiangbing DU, Lin Ma, Zuyuan He, Ming-jun LI, Jian Wang
Summary: In this paper, three OAM modes and 22 wavelength channels are multiplexed and transmitted using an OAM distributed Raman amplifier and a homemade all-fiber OAM (de)multiplexer. The performance of the OAM DRA is characterized using two pump configurations. The results show the successful implementation of long-distance OAM mode multiplexing transmission with favorable performance.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2023)
Article
Optics
Shuang Liu, Junyi Hu, Yuxin Wang, Qingwen Liu, Huilian Ma, Zuyuan He
Summary: A broadband source-driven RMOG based on a multi-turn waveguide-type ring resonator has been proposed and demonstrated, showing improved long-term bias stability and reduced relative intensity noise-induced error. By optimizing the number of loop turns, the angle random walk is also improved compared to a single-turn WRR. The achieved bias stability of 1/h with a 5-turn WRR of 4.05 cm diameter is considered the best result reported to date for an RMOG of similar size.
Letter
Computer Science, Information Systems
Linjing Huang, Zuyuan He, Xinyu Fan
Summary: A simplified single-end Rayleigh/Brillouin hybrid distributed sensing system is proposed and experimentally demonstrated, which can simultaneously measure static parameters and dynamic parameters by integrating BOTDA for static parameters and phi-OTDR for dynamic parameters. A high-performance hybrid system is achieved by carefully designing parameters considering the interaction between Rayleigh and Brillouin processes.
SCIENCE CHINA-INFORMATION SCIENCES
(2023)
Article
Optics
Haijun He, Lin Jiang, Yan Pan, Anlin Yi, Xihua Zou, Wei Pan, Alan E. Willner, Xinyu Fan, Zuyuan He, Lianshan Yan
Summary: The integration of high-speed optical communication and distributed sensing in fibre networks brings intelligent functionalities and improves transmission performance. This work demonstrates an integrated scheme using the same wavelength channel for data transmission and distributed vibration sensing, achieving improved performance and larger launching power. Experimental results show high resolution and frequency response in vibration sensing, offering a new path for exploring the potential of fibre-optic networks and measuring non-linear parameters in coherent optical communications.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Yuanpeng Deng, Qingwen Liu, Shuting Liu, Zuyuan He
Summary: This article proposes a multipath quasi-distributed acoustic sensing system based on time-gated digital optical frequency-domain reflectometry (TGD-OFDR) and space division multiplexing (SDM) technique. The system efficiently utilizes the single-mode fiber (SMF) segment between weak reflectors to simultaneously monitor multiple sensing arrays. Experimental results demonstrate the successful detection of vibrations on two weak reflectors array and analysis of crosstalk between paths. This multipath system has great potential in large-scale sensing network without requiring additional hardware equipment and sacrificing system bandwidth.
IEEE SENSORS JOURNAL
(2023)
Article
Optics
Yangyang Wan, Xinyu Fan, Bingxin Xu, Zuyuan He
Summary: A specially designed neural network is proposed for reconstructive wavemeter based on temporal speckle, combining a physical model and data-driven model. With only 10 μs, it obtains a reference speckle for the generation of a training dataset. The neural network achieves a spectral resolution of 3.2 fm and the largest dynamic range of 2300 output channels, demonstrating its capability to resolve unseen spectrum with multi-tone wavelengths and better robustness in long-time measurement compared to data-driven model based networks.
LASER & PHOTONICS REVIEWS
(2023)
Article
Optics
Jiacheng Liu, Jiangbing Du, Weihong Shen, Linjie Zhou, Wenjia Zhang, Zuyuan He
Summary: Due to the resonant nature and silicon's strong optical nonlinearity, the performance of silicon micro-ring modulators can be affected by the input optical power. In this study, a multi-mode silicon micro-ring modulator operating in the TE1 mode was proposed and experimentally demonstrated to mitigate optical nonlinear effects. The TE1 mode, with larger waveguide loss and mode effective area, features a higher nonlinear threshold compared to the TE0 mode. The resonance spectrum maintained a symmetric Lorentz shape with a minimal shift in resonance wavelength under 10 mW optical input power, indicating improved robustness to optical nonlinearity compared to regular silicon micro-ring modulators.
Article
Optics
Shuang Liu, Junyi Hu, Yuxin Wang, Qingwen Liu, Huilian Ma, Zuyuan He
Summary: This article introduces a novel configuration of a three-axis resonant fiber-optic gyroscope (RFOG) with a multiplexed broadband light source, which can measure rotation rates in three directions simultaneously. The interference between different axial gyroscopes is effectively avoided by optimizing the lengths of three fiber-optic ring resonators (FRRs). A navigation-grade three-axis RFOG is demonstrated in the end.
Article
Engineering, Electrical & Electronic
Yue Jiang, Wenjia Zhang, Xuying Liu, Wenyu Zhu, Jiangbin Du, Zuyuan He
Summary: Photonic convolution neural network (CNN) has the ability to provide Tera-level operations/sec (OPS) for object detection with low energy consumption. However, its operating precision is lower than that of electronic AI accelerators due to noise constraints. A digital-analog co-designed photonic CNN using error learning and Kirsch edge enhancement is proposed, achieving 96.1% recognition accuracy at 2-bit precision. The architecture shows promise for high-speed computing with energy efficiency.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Linjing Huang, Xinyu Fan, Zuyuan He
Summary: Distributed fiber-optic sensing system is widely used for temperature and strain measurement in health monitoring of various structures. A single-end multi-parameter sensing system is proposed and demonstrated, which integrates Brillouin optical time domain analyzer (BOTDA) for static parameters and phase-sensitive optical time domain reflectometry (?-OTDR) for dynamic parameters.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Yunhe Zhao, Huiqin Peng, Yuehui Ma, Yunqi Liu, Yongsheng Yang, Zuyuan He
Summary: In this work, we demonstrate the multiparametric monitoring of directional bending, torsion, and temperature by using helical long-period gratings (HLPGs) in a triangular four-core fiber (FCF) through CO2 laser irradiation. The stress-relaxing effect of the stress-applying parts due to CO2 laser heating is investigated through simulations. Experimental results show that the FCF-HLPGs with a period of 435 μm and a period number of 60 exhibit good sensing characteristics for multiparametric monitoring. The proposed FCF-HLPGs have potential practical applications in multiparametric monitoring.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Yue Jiang, Wenjia Zhang, Xuying Liu, Zuyuan He
Summary: We propose and demonstrate an efficient batch dimension processing scheme based on the micro-ring weighting bank, which can significantly increase the computing capability of the photonic tensor core without requiring additional weighting units and power consumption.
2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Xuying Liu, Wenjia Zhang, Yue Jiang, Dan Lu, Fan Yang, Zuyuan He
Summary: We propose an integrated W-band transmitter enabled by a dual-mode DFB laser and silicon microring modulator for next-generation wireless communication. The experimental results demonstrate error-free transmission of 10 Gb/s communication at 85 GHz by utilizing off-chip free-running and on-chip DFB laser.
2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC
(2023)
Article
Optics
Yunhe Zhao, Ziyang Hua, Mengxue Tang, Huiqin Peng, Siyu Chen, Yuehui Ma, Yunqi Liu, Zuyuan He
Summary: A high-sensitivity bending sensor based on dual-dip long period fiber gratings (LPFGs) in a single-mode fiber is proposed. The sensor exhibits high bending sensitivity and eliminates cross-sensitivity to temperature.
OPTICS COMMUNICATIONS
(2023)
