Author Affiliations
Abstract
1 Institute of Artificial Intelligence, University of Science and Technology Beijing (USTB), Beijing 100083, China
2 Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong 999077, China
3 MACOM Technology Solutions, Shenzhen 518000, China
4 Department of Electrical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong 999077, China
Stokes vectors direct detection (SV-DD) is an effective solution for short-reach optical communications. In this Letter, we investigate two-dimensional-modulation direct-detection systems based on three Stokes vector receivers (SVRs). The influences of three key factors including the states-of-polarization (SOP), the splitting ratio of the coupler, and the excess loss (EL) are studied in detail. It is shown that the splitting ratio for achieving optimum performance will be changed with SOP and EL conditions. Among these SVRs, the 3×3 coupler-based receiver with its optimal splitting ratio shows the best bit error rate performance and stability against the change of SOP.
060.2330 Fiber optics communications 060.4080 Modulation Chinese Optics Letters
2018, 16(10): 100605
Author Affiliations
Abstract
1 COMSATS Institute of Information Technology (CIIT), Islamabad, Pakistan
2 Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hong Kong, China
3 National University of Sciences and Technology (NUST), Islamabad, Pakistan
In this Letter, we have proposed a generalized Gaussian probability density function (GGPDF)-based method to estimate the symbol error ratio (SER) for pulse amplitude modulation (PAM-4) in an intensity modulation/direct detection (IM/DD) system. Furthermore, a closed form expression of SERGGD for PAM-4 has been derived. The performance of the proposed method is evaluated through simulation as well as experimental work. The fitting of probability density functions of the received signal is applied via GGPDF and shape parameters P1 and P2 associated with different PAM-4 levels are determined. The optimum single value of shape parameter P is then calculated to estimate the SER. The mathematical relationship of P with different received optical powers and receiver bandwidths has been determined and verified. The proposed method is a fast and accurate method to estimate SER of a PAM-4 system, which is more reliable and in agreement with the error counting method.
060.4510 Optical communications Chinese Optics Letters
2018, 16(4): 040604
Author Affiliations
Abstract
1 Department of Electronic and Information Engineering, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055, China
2 Photonics Research Center, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
3 Photonics Research Center, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hong Kong, China
We propose and experimentally demonstrate a universal and blind polarization-state tracking scheme for M-quadrature amplitude modulation (QAM) signals based on a decision-free radius-directed linear Kalman filter (RD-LKF). The polarization tracking performance is investigated through simulation and experiments for both quadrature phase-shift keying (QPSK) and 16-QAM signals. The influence of the filter parameters on the static polarization demultiplexing performance and dynamic tracking capability are discussed via simulation. The optimization strategy of the filter parameters in modulation-format-independent scenarios is proposed and simulations are carried out to evaluate the polarization demultiplexing penalty for QPSK, 16QAM, and hybrid QPSK/16QAM signals. Finally, the proposed decision-free RD-LKF is experimentally compared to the respective algorithms of constant modulus algorithm and multimodulus algorithm for QPSK and 16-QAM and the advantage of ultrafast polarization tracking ability is confirmed.
060.1660 Coherent communications 120.3930 Metrological instrumentation Chinese Optics Letters
2016, 14(11): 110601
1 北京交通大学全光网络与现代通信网教育部重点实验室, 北京 100044
2 北京交通大学光波技术研究所, 北京 100044
提出一种基于线性相位插值(LPI)的增强型载波相位估计(CPE)算法，并对其在112 Gb/s偏振复用16进制正交幅度调制（DP-16QAM）系统中的性能进行了仿真和实验研究。该算法在基于数据块平均的CPE算法基础上，通过对其获得的估计相位噪声进行LPI，实现相位噪声估计准确度的大幅提升。仿真结果显示，基于CPE的增强型CPE算法的相位估计误差的方差比基于数据块平均的算法降低了26%。同时，其线宽容忍度是基于数据块平均算法的2倍。在112 Gb/s DP-16QAM实验系统中对增强型算法进行了测试。实验结果表明，在误码率(BER)为3.8×10-3处，采用增强型算法时所需光信噪比(OSNR)比基于数据块平均算法降低了0.7 dB。仿真与实验结果显示，基于LPI的CPE算法性能与基于窗口扫描算法相当，但增强型算法的硬件复杂度降低了99.2%。
光通信 载波相位估计 相干检测 数字信号处理 正交幅度调制
Author Affiliations
Abstract
The 10-Gb/s non-return-to-zero (NRZ) on-off-keying (OOK) data transmission over a 100-km transmission fiber link employing an all fiber 1.55-\mu m single longitudinal mode (SLM) distributed Bragg reflector (DBR) fiber laser as the signal source is demonstrated. The experimental result is comparable with that of the transmission system by using a commercially semiconductor distributed feedback (DFB) laser.
060.3510 Lasers, fiber 060.2330 Fiber optics communications 060.2360 Fiber optics links and subsystems 060.2380 Fiber optics sources and detectors Chinese Optics Letters
2012, 10(s2): S20602
全光网络与现代通信网教育部重点实验室 北京交通大学，北京 100044
文章提出一种在光纤光栅自身热膨胀效应产生啁啾的基础上，利用铝片热膨胀系数比较高的特点产生应力来增强光纤光栅啁啾，从而实现了宽带、大范围色散调谐的新型光纤光栅色散补偿器。该色散补偿器能够分别对群速度色散及中心波长独立调谐。实验结果表明，在中心波长为1 551.25 nm处，能够实现＞1.5 nm的色散补偿带宽，-350～-690 ps/nm的群时延色散调谐范围；在色散为-660 ps/nm情况下，能够实现中心波长1 nm的偏移。
光通信 光纤光栅 色散补偿 调谐 宽带 optical communication fiber grating dispersion compensation tuning wideband
Author Affiliations
Abstract
A temperature independent 80-Gb/s 100-km transmission system is demonstrated with the use of spectral phase modulation-based tunable dispersion compensator (TDC). The principle of dispersion compensation based on spectral phase modulation as well as the relationship between spectral phase modulation function and group velocity dispersion (GVD) are theoretically studied. TDC based on spectral phase modulation is implemented. The performance of 80-Gb/s transmission system is experimentally evaluated. The non-linear relationship between temperature and temperature-induced dispersion fluctuations is demonstrated through the asymmetric temperature-induced power penalty without dispersion compensation. With respect to the low temperature area, the temperature-induced dispersion fluctuations are smaller than those in the high temperature area. By using the proposed TDC, temperature independent 80-Gb/s transmission is successfully demonstrated under a temperature range of –20 – 60 C with a power penalty of less than 0.8 dB.
060.4230 Multiplexing 060.2360 Fiber optics links and subsystems 060.2330 Fiber optics communications 060.4510 Optical communications 060.5060 Phase modulation Chinese Optics Letters
2012, 10(2): 020602
Author Affiliations
Abstract
1 Key Lab of All Optical Networks and Advanced Communication Network of EMC, Beijing Jiaotong University, Beijing 100044, China
2 Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044, China
A single channel with a 160-Gb/s optical time-division-multiplexing (OTDM) transmission over 100 km is fabricated. With the help of 500-GHz optical sampling oscilloscopes, the fiber length is adjusted to the order of 10 m, which corresponds to the accuracy of 0.4 ps for the dispersion compensation. The dispersion map is optimized for the 100-km transmission link. A completely error-free transmission with the power penalty of 3.6 dB is achieved for 2 h without using forward error correction.
光时分复用 高精度色散补偿 色散管理 060.2330 Fiber optics communications 060.2360 Fiber optics links and subsystems 060.4230 Multiplexing 060.4256 Networks, network optimization 060.2400 Fiber properties Chinese Optics Letters
2010, 8(8): 741
