Author Affiliations
Abstract
Key Laboratory for Information Science of Electromagnetic Waves (MoE), Fudan University, Shanghai 200433, China
We propose a two-cascaded, constant-resistance, symmetrical bridged-T amplitude equalizer for a high-speed visible light communication (VLC) system. With the pre-equalization circuit, the 3 dB bandwidth of the VLC system can be extended from 12 to 235 MHz using a commercially available phosphorescent white light-emitting diode (LED), a blue filter, and a low-cost PIN photodiode. The data rate is 1.20 Gbit/s, exploiting 16-quadrature amplitude modulation-orthogonal frequency-division multiplexing with a 300 MHz modulation bandwidth over 50 cm of free-space transmission under the pre-forward error correction limit of 3.8×10 3. To our knowledge, this is the highest 3 dB bandwidth and the highest data rate ever achieved by using a pre-equalization circuit and white LED in a VLC system.
060.2605 Free-space optical communication 060.4080 Modulation 070.4340 Nonlinear optical signal processing Chinese Optics Letters
2015, 13(10): 100602
在长距离光通信系统中,采用高阶外调制和相干接收技术来提高系统总的传输容量。但是在短距离光通信系统中更倾向于使用低成本的直接调制-直接检测技术, 此时, 要实现高速、大容量传输就必须采用多电平调制。目前国际上主流的调制方案有三种: PAM(脉冲幅度调制)、DD-OFDM(直接检测-正交频分复用)调制和CAP(无载波幅度相位)调制, 文章对这三种方案的原理与性能进行了分析与比较, 希望以此作为未来短距离大容量光通信系统设计的依据。
短距离光通信 脉冲幅度调制 无载波幅度相位调制 直接检测-正交频分复用 short-haul optical communication PAM CAP modulation DD-OFDM
Author Affiliations
Abstract
We propose and experimentally demonstrate a novel scheme to realize polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) signal transmission over fiber, wireless and fiber at W-band (75-110 GHz). The generation of polarization multiplexing millimeter-wave (mm-wave) wireless signal is based on the photonic technique. After 20-km fiber transmission, polarization diversity and heterodyne beating are implemented to convert the polarization components of the polarization-multiplexing signals from the optical baseband to W-band so that up to 16 Gb/s mm-wave signals can be delivered over 2-m 2×2 multiple-input multiple-output (MIMO) wireless link. At the receiver base station (BS), polarization combination reconstructs the PDM-QPSK signal which is then launched into another 20-km fiber. In the experiment, coherent detection is introduced to improve receiver sensitivity and constant modulus algorithm (CMA) is applied for polarization de-multiplexing. The bit-error-ratio (BER) for 16-Gb/s PDM-QPSK signal delivery is below the forward-error-correction (FEC) threshold of 3.8×10-3 with the optical signal-to-noise ratio (OSNR) above 11.8 dB.
060.0060 Fiber optics and optical communications 060.5625 Radio frequency photonics Chinese Optics Letters
2014, 12(5): 050603
Author Affiliations
Abstract
We report a 3.75-Gb/s visible light communication (VLC) system thatusessingle-carrier frequency-domain equalization (SC-FDE) based on a single red–green–blue (RGB) light-emitting diode (LED), with the measured bit error rates (BERs) under a pre-forward-error-correction threshold of 3.8 \times 10-3. The fundamental characteristics of an RGB-LED-based VLC system are measured. We also compare SC-FDE with OFDM in terms of peak-to-average power ratio and BER performance, which shows that SC-FDE outperforms the OFDM modulation scheme.
060.0060 Fiber optics and optical communications 060.4080 Modulation 060.2605 Free-space optical communication Chinese Optics Letters
2014, 12(1): 010605
1 复旦大学 通信科学与工程系，上海200433
2 武汉理工大学 信息工程学院，湖北 武汉430070
VLC（可见光通信）是一种新兴的无线光通信技术，它兼具照明和通信，具有多项优势和广阔的应用前景，已成为近年来研究的热点，结合MIMO（多输入多输出）等技术，可以大大提高其通信速率。研究人员已经提出了多种可用于 VLC的MIMO模型和技术，国际上基于MIMO的光通信系统的研究有多点漫射MIMO系统、像素化MIMO系统、非成像MIMO系统和成像MIMO系统。文章对这些系统进行了探讨，总结了各种光MIMO通信模型的优缺点，可作为深入理解和进一步研究可见光MIMO通信技术的基础。
可见光通信 多输入多输出 多点漫射 像素化 非成像可见光通信 成像可见光通信 VLC MIMO multispot diffuse pixilated nonimaging VLC imaging VLC
