Article
Optics
J. U. N. T. I. N. G. Shi, J. I. A. N. J. U. N. Yu, J. I. A. O. Zhang, M. I. N. Zhu, L. O. N. G. Zhang, K. A. I. H. U. I. Wang, W. E. N. Zhou, T. A. N. G. Y. A. O. Xie, J. I. A. N. G. U. O. Yu
Summary: In this study, the transmission of a 65,536-ary quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) signal supported by a hybrid fiber-terahertz (THz) multiple-input multiple-output (MIMO) system at 320 GHz is demonstrated. The use of polarization division multiplexing (PDM) technique doubles the spectral efficiency. By employing 2-bit deltasigma modulation (DSM) quantization, a 65,536-QAM OFDM signal is successfully transmitted over a 20-km standard singlemode fiber (SSMF) and a 3-m 2x2 MIMO wireless delivery, achieving a net rate of 60.5 Gbit/s for THz-over-fiber transport. This study also achieves a maximum signal-to-noise ratio (SNR) of 52.6 dB below the fronthaul error vector magnitude (EVM) threshold of 0.34%, marking the highest achievable modulation order for DSM applications in THz communication.
Article
Optics
Jasmeet Singh, Andreas Ahrens, Steffen Lochmann
Summary: MIMO technology in optical communication can improve data rates and capacity demands, while improving efficiency and reducing complexity through the joint design of pre-equalization and post-equalization. This technology can also effectively reduce bit-error rate and increase received optical power.
Article
Engineering, Electrical & Electronic
Xiong Deng, Wenxiang Fan, Thiago E. Bitencourt Cunha, Shuai Ma, Chen Chen, Yixian Dong, Xihua Zou, Lianshan Yan, Jean-Paul M. G. Linnartz
Summary: The paper proposes a two-dimensional water-filling (2D-WF) power allocation algorithm that operates in frequency and space domains to improve the rate achieved by MIMO-OFDM VLC systems over low-pass VLC channels. Simulation results demonstrate that the proposed 2D-WF power allocation outperforms other schemes in terms of achievable bit rate in typical indoor environments.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2022)
Article
Optics
Ye Zhou, Jun Ming, Leilei Wang, Dongyan Wu, Li Zhao, Jiangnan Xiao
Summary: The dual sidebands of the independent dual-SSB signal can carry different information, achieving higher spectral efficiency and system capacity. A proposed detection scheme based on a single PD and DSP reduces the complexity and cost of the receiver. After 50 km of fiber transmission, the dual-SSB signal is successfully extracted with a bit error rate below the hard-decision forward-error-correction threshold.
Article
Optics
Juan M. Marin, Islam Ashry, Omar Alkhazragi, Abderrahmen Trichili, Tien Khee Ng, Boon S. Ooi, Boon s. Ooi
Summary: This article describes the design and testing of a distributed acoustic sensing (DAS) system that co-exists with optical communication, enabling high-speed data transmission and vibration detection over optical fibers.
Article
Optics
Joseph C. Chapman, Alexander Miloshevsky, Hsuan-Hao Lu, Nageswara Rao, Muneer Alshowkan, Nicholas A. Peters
Summary: Squeezed light is essential for quantum information science. This study demonstrates the measurement of coexistent two-mode squeezing after distribution through separate fiber spools and deployed campus fibers. The squeezed modes do not require dedicated dark fiber and can be used for future applications in quantum networks and sensing.
Article
Engineering, Electrical & Electronic
Usha Choudhary, Vijay Janyani, Muhammad Arif Khan
Summary: This paper introduces a revised ACO-OFDM frame for DD-IM systems to improve bandwidth efficiency and transmission power. By retaining discarded negative polarity symbols, a dual frame OFDM architecture is proposed, showing lower BER values compared to the PCSC scheme.
OPTICAL AND QUANTUM ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Kewei Li, Fan Wang, Wenhua Ren, Xinyang Liu, Li'ang Zhang, Xin Lv, Guobin Ren, Xinbo Zheng
Summary: This work proposes and experimentally demonstrates a multi-wavelength fiber laser with a high-purity LP11 output mode. By utilizing a novel symmetrical fiber mode selective coupler for mode conversion and a Sagnac interferometer as a multi-channel filter for wavelength selection, the laser is able to achieve stable single-, dual-, and triple-wavelength outputs around 1530nm and 1550nm with high purity LP11 mode.
OPTICAL FIBER TECHNOLOGY
(2023)
Article
Optics
Junyi Liu, Zhenrui Lin, He Zhu, Lei Shen, Shuqi Mo, Zhenhua Li, Jingxing Zhang, Junwei Zhang, Xiaobo Lan, Jie Liu, Siyuan Yu
Summary: This experiment successfully demonstrated the transmission of 14 multiplexed OAM channels, each carrying 80 wavelengths, over a 100-km single-span ring-core fiber with record spectral-efficiency distance product. The system requires low-complexity equalization at the receiving end to deal with crosstalk among highly degenerate intra-MG modes, showing great potential in large-capacity and relatively long-distance MDM transmissions.
Article
Optics
Shuqi Zhang, Qinghua Wang, Wei Zhou, An Yan, Junwen Zhang, Jianyang Shi, Nan Chi, Ziwei Li
Summary: This study proposes a spatial pilot-aided learning framework for multi-mode fiber (MMF) image transmission, addressing the challenges posed by scattering and time varying nature of MMFs. The framework adapts to physical channel variations and allows continuous transmission through a fast-adapt network training scheme. Experimental results demonstrate high transmission accuracy and reduced computation time compared to conventional approaches.
Article
Engineering, Electrical & Electronic
Yuqin Zhang, Yudong Lian, Yuhe Wang, Jingbo Wang, Mengxin Yang, Nannan Luan, Yulei Wang, Zhiwei Lu
Summary: This paper introduces a multi-core fiber with the ability to operate in dual mode under certain conditions. By adjusting structural parameters, the effective area of the fundamental mode can be increased and bending loss can be reduced. The flexibility of the structure makes this fiber significant for both theoretical research and practical manufacturing.
OPTICAL FIBER TECHNOLOGY
(2021)
Article
Optics
Ye Zhou, Jiangnan Xiao, Chuang Zhao, Jiangli Zuo, Jun Ming, Li Zhao
Summary: This paper introduces a new scheme for twin-single-sideband (twin-SSB) signals, which improves system performance by separating the LSB and RSB signals using a single-ended photodetector at the receiver. The simulation results demonstrate that the proposed scheme achieves low bit error ratio (BER) for different modulation formats and baud rates.
Article
Computer Science, Information Systems
Guillem Femenias, Felip Riera-Palou
Summary: This paper investigates the impact of doubly selective fading channels on the design and performance analysis of cell-free massive MIMO-OFDM networks. The proposed double selectivity-aware channel estimation/prediction schemes and combining/precoding strategies are evaluated through extensive numerical simulations under different degrees of time and frequency selectivity.
Article
Optics
Qi Qin, Fengping Yan, Yan Liu, Luna Zhang, Ying Guo, Wenguo Han, Zhuoya Bai, Ting Feng, Hong Zhou
Summary: A switchable, thulium-doped, isolator-free fiber laser with single and dual-wavelength operations was proposed and demonstrated. The laser achieved stable operation through specific design and adjustments, with minimal wavelength drift and power fluctuation at room temperature.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Optics
Chen Wang, Jianjun Yu, Jiao Zhang, Min Zhu, Yuxuan Tan, Kaihui Wang, Junjie Ding, Wen Zhou, Tangyao Xie, Jianguo Yu, Feng Zhao
Summary: We have successfully implemented a 320-GHz 320-Gbps/? terahertz (THz) radio-over-fiber (RoF) system using a photonics-aided scheme with the help of polarization-division multiplexing (PDM) technology and multiple-input, multiple-output (MIMO) transmission. The system utilizes a low-complexity MIMO single-carrier frequency-domain equalizer (SCFDE) to compensate for polarization-related impairments and compares the performance of SCFDE and the commonly used constant modulus algorithm (CMA) for demultiplexing. After transmission through a 20-km standard single-mode fiber (SSMF) and 3-m 2x2 MIMO wireless link, the received 46-GBaud PDM 16-ary quadrature amplitude modulation (16QAM) signal achieves a bit error rate (BER) that satisfies the soft-decision forward error correction (SD-FEC) threshold with 15% overhead, corresponding to a record-breaking net bit rate of 320 Gbit/s.
Article
Optics
William Shieh, Chuanbowen Sun, Honglin Ji
LIGHT-SCIENCE & APPLICATIONS
(2020)
Article
Optics
Honglin Ji, Xian Zhou, Chuanbowen Sun, William Shieh
Article
Optics
Zhaopeng Xu, Chuanbowen Sun, Tonghui Ji, Jonathan H. Manton, William Shieh
Editorial Material
Engineering, Electrical & Electronic
R. Doverspike, D. Kuchta, W. Shieh, D. Plant, S. Matsuo, J. S. Wey
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Tonghui Ji, Chuanbowen Sun, Honglin Ji, Zhaopeng Xu, Yunfeng Peng, William Shieh
Summary: In this article, a new interleaved subcarrier loading scheme for double-sideband signals is proposed to achieve optical field recovery at low CSPRs in self-coherent detection systems. Theoretical and simulation results show that the proposed scheme can work under lower CSPRs than previous systems, with almost the same electrical spectral efficiency. Additionally, the process of parameter optimization for the interleaved CADD scheme is illustrated, leading to successful transmission of 100-Gbps 16-QAM OFDM signals over 160-km fiber at 3.5-dB CSPR.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Zhaopeng Xu, Chuanbowen Su, Tonghui Ji, Jonathan H. Manton, William Shieh
Summary: In this article, transfer learning (TL)-aided feedforward neural networks (FNN) and recurrent neural networks (RNN) are proposed for nonlinear equalization in short-reach direct detection optical links, allowing for a fast transition to new equalizers when the channel condition changes. TL significantly reduces the training requirements of FNNs/RNNs in the target system, with a substantial decrease in epochs and training symbols. Additionally, it is found that FNNs can be effectively transferred to their corresponding RNNs for equalization in the target system.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Xian Zhou, Yuyuan Gao, Jiahao Huo, William Shieh
Summary: This article thoroughly analyzes the influence of phase noise on the self-homodyne coherent system and discusses the unique property that system performance is only related to the product of linewidth and mismatch length in the absence of carrier phase recovery. It is found that for SHC-16QAM systems, the product of laser linewidth and delay mismatch should be kept below 0.18 MHz .m to limit the OSNR penalty to below 1-dB, with no CPR algorithm required under such conditions. Additionally, the phase noise tolerance of SHC and conventional coherent systems are similar in the presence of CPR.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Zhaopeng Xu, Chuanbowen Sun, Jonathan H. Manton, William Shieh
Summary: Various neural network-based equalizers are proposed for short-reach optical direct detection communication systems, with novel DSP schemes designed to handle both linear and nonlinear impairments. Experimental results demonstrate that cascade FNN/RNN and FNN/RNN-FFE can improve BER performance, while using DFE in place of FFE does not show significant improvement.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2021)
Article
Optics
Jingchi Li, Shaohua An, Honglin Ji, Xingfeng Li, William Shieh, Yikai Su
Summary: The parallel dual delay-based CADD method reduces the required guard band by placing an additional delay parallel to the original delay in conventional CADD, resulting in a sharper roll-off edge around the zero frequency in the modified transfer function. This allows for maximized bandwidth utilization of the system.
Review
Chemistry, Multidisciplinary
Isiaka Alimi, Romil Patel, Nuno Silva, Chuanbowen Sun, Honglin Ji, William Shieh, Armando Pinto, Nelson Muga
Summary: This paper reviews recent progress on different high-speed optical short- and medium-reach transmission systems, presents a tutorial on high-performance, low-cost, and advanced optical transceiver (TRx) paradigms, and extensively discusses recent advances in high-performance digital signal processing algorithms and innovative optoelectronic components. It also explores the reconfigurable and sliceable TRxs to address the dynamic environment and heterogeneous nature of applications and services supported by the systems, reviewing the associated technical challenges and proposing viable solutions.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Electrical & Electronic
Honglin Ji, Jingchi Li, Xingfeng Li, Shuangyu Dong, Zhaopeng Xu, Yikai Su, William Shieh
Summary: This paper proposes a complementary polarization-diversity coherent receiver (C-PDCR) using remote LO, which enables rapid polarization tracking. Experimental results demonstrate the significant improvement achieved by this method under high-speed polarization rotation rates.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Zhaopeng Xu, Shuangyu Dong, Jonathan H. Manton, William Shieh
Summary: With the rapid development of machine learning technologies, neural network (NN)-based equalizers have been proven to be efficient tools for dealing with nonlinear impairments in optical interconnects. However, the computational complexity (CC) of these equalizers remains a major concern. This paper proposes an NN-based multi-symbol equalization scheme inspired by multi-task learning to significantly reduce CC.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Honglin Ji, Shuangyu Dong, Zhaopeng Xu, Jingchi Li, Ranjith Rajasekharan Unnithan, Yikai Su, William Shieh
Summary: Coherent detection offers optical field recovery for channel impairment compensation and advanced modulation formats, while direct detection is more cost-effective. A simplified CADD scheme is proposed to combine the advantages of both methods, with SSBI iterative mitigation algorithms introduced.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Optics
Xingfeng Li, Shaohua An, Honglin Ji, Jingchi Li, William Shieh, Yikai Su
Summary: In this paper, a deep-learning-enabled direct detection scheme is proposed to recover the transmitted signal. The scheme reduces the carrier to signal power ratio (CSPR) and achieves cost reduction and performance improvement. It is suitable for applications such as data center interconnects.
Article
Engineering, Electrical & Electronic
Chuanbowen Sun, Tonghui Ji, Honglin Ji, Zhaopeng Xu, William Shieh
IEEE PHOTONICS TECHNOLOGY LETTERS
(2020)
