Author Affiliations
Abstract
1 Key Laboratory of EMW Information (MoE), Fudan University, Shanghai 200433, China
2 Department of Communication Science and Engineering, Shanghai ERC of LEO Satellite Communication and Applications, Shanghai CIC of LEO Satellite Communication Technology, Fudan University, Shanghai 200433, China
3 Department of Electronic Engineering, Jinan University, Guangzhou 510632, China
4 School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China
Increasing bandwidth requirements have posed significant challenges for traditional access networks. It is difficult for intensity modulation/direct detection to meet the power budget and flexibility requirements of the next-generation passive optical network (PON) at 100G and beyond considering the new requirements. This is driving researchers to develop novel optical access technologies. Low-cost, wide-coverage, and high-flexibility coherent PON is emerging as a strong contender in the competition. In this article, we will review technologies that reduce the complexity of coherent PON (CPON), enabling it to meet the commercial requirements. Also, advanced algorithms and architectures that can enhance system coverage and flexibility are also discussed.
access network coherent optics flexible data rate low complexity wide dynamic range Chinese Optics Letters
2024, 22(4): 040604
光通信研究
2024, 50(1): 23014301
暨南大学信息科学技术学院,广东 广州 510632
为了提高水下光无线通信(UOWC)的频谱效率和功率效率,提出了一种基于多层非对称剪裁光正交频分复用(Layered-ACO-OFDM)的UOWC系统。该系统通过对子载波分层调制的方法,充分利用了传统非对称剪裁光正交频分复用(ACO-OFDM)中损失的频谱资源,极大地提高了光无线通信系统的频谱效率。此外,Layered-ACO-OFDM系统不需要加入直流偏置,故功率效率也得到了大大提升。考虑了可见光在海水中传输过程中的吸收和散射效应,建立了基于蒙特卡罗方法的UOWC信道模型,并较为全面地研究了海水中不同叶绿素浓度和不同接收机参数下的信道响应。结果表明,与传统ACO-OFDM相比,基于Layered-ACO-OFDM的UOWC系统具有频谱效率高的优势。同时,当信噪比为27 dB时,在清澈海水中其可以实现10 m距离下1 Gb/s的高速率通信。
光通信 多层非对称剪裁光正交频分复用系统 频谱效率 蒙特卡罗仿真 信道特征 水下光无线通信 激光与光电子学进展
2021, 58(21): 2106005
Author Affiliations
Abstract
1 School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510006, China
2 Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou 510632, China
This paper firstly, to the best of our knowledge, proposed two-dimensional (2D) encryption based on the Arnold transformation for implementing a secure DC-biased optical orthogonal time-frequency multiplexing (DCO-OTFM) in optical-wireless communications (OWCs). The encrypted data is transformed to the particular 2D matrix and decrypted by the only key to get the correct information. Meanwhile, the number of keys in 2D encryption is enormous, which prevents eavesdroppers from exhaustively searching secret keys rapidly to find the right decryption. Numerical results demonstrate that the secure DCO-OTFM based on 2D encryption can effectively prevent signal decryption from the eavesdropper, which has good secure performance for applying in OWC.
orthogonal time-frequency multiplexing two-dimensional encryption physical layer security optical-wireless communications Chinese Optics Letters
2021, 19(5): 050603
Author Affiliations
Abstract
1 Beijing Key Laboratory of Space-Ground Interconnection and Convergence, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China
2 Institute of Electronic and Information Industry, China Center for Information Industry Development, Beijing 100876, China
3 Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou 510632, China
This paper proposes a hybrid layered asymmetrically clipped optical (HLACO) single-carrier frequency-division multiplexing (SCFDM) scheme for dimmable visible light communication. It designs a signal structure that combines layered asymmetrically clipped optical (LACO)-SCFDM and negative LACO-SCFDM in proportion for improving the inherent weaknesses of orthogonal frequency-division multiplexing (OFDM)-based dimmable schemes and further enhancing the system performance. Compared to the HLACO-OFDM-based dimming scheme, it obtains a lower bit error ratio and enables efficient communication over broader dimming range. Its spectral efficiency realizes 2.875 bit·s-1·Hz-1 within the dimming range of 30%–70%, and the attainable average spectral efficiency gains exceed at least 19.21% compared to other traditional dimmable schemes.
dimming control single-carrier frequency-division multiplexing visible light communication spectral efficiency complexity Chinese Optics Letters
2021, 19(4): 040601
Author Affiliations
Abstract
State Laboratory of Information Photonics and Optical Communications, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China
In this Letter, we propose a scheme that integrates a diversity-combining technique with asymmetrical clipping optical orthogonal frequency-division multiplexing (ACO-OFDM) based on a discreet Hartley transform (DHT). Simulations are demonstrated for the DHT-based ACO-OFDM system with a diversity-combining technique. The simulation results indicate that when the optimal weighting factor is chosen, the bit error rate (BER) performance is improved by about 2 dB when the binary phase-shift keying (BPSK) is modulated and about 3 dB when the 16 pulse-amplitude modulation is modulated. Additionally, experiments are presented to verify the feasibility of diversity-combining DHT-based ACO-OFDM. In the transmission experiments, a BPSK-modulated DHT-based ACO-OFDM with a diversity-combining receiver is realized, which improves the BER performance by 1.5 and 1.3 dB for a span length of back-to-back and a 50 km standard single-mode fiber, respectively.
Chinese Optics Letters
2015, 13(Suppl): S20605
北京邮电大学 信息与通信工程学院 信息光子学与光通信国家重点实验室, 北京 100876
为了得到高性能的多载波光源,研究了射频信号中不同相位差对光多载波的影响.通过理论分析可得,随着相位差从90°降至0°,光多载波性能会逐渐变差,但是相位差偏与90°相差不大时,性能不会下降太多.实验中通过移相器改变相位差,使相位差为90°,45°,0°,得到循环前IQ调制器的输出光谱,并对比循环后光多载波性能.实验结果显示,相位差为90°时,循环前IQ调制器输出为较好的单边带光谱,循环后输出50条平坦稳定光多载波;相位差为45°时,光多载波质量变差;相位差为0°时,得不到光多载波.因此,射频信号相位差为90°时,光多载波的性能最佳,随着相位差变小,性能下降,但是相位差为45°时,产生的光多载波仍可应用于光通信.
光通信 多载波 循环移频 相偏 稳定平坦 Optical communication Multicarrier RFS Phase deviation Stability and flatness