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Wang Z.,Fudan University | Wang Z.,National Engineering Research Center for Broadband Networks and Applications | Tao L.,Fudan University | Wang Y.,Fudan University | Chi N.,Fudan University
Chinese Optics Letters | Year: 2015

Carrierless amplitude and phase (CAP) modulation is generating increasing interest for short-reach optical communications. Polarization multiplexing (PolMux) is a good way to improve the CAP system's data rate further with the limited bandwidth of electrical devices. In this Letter, we experimentally demonstrate a 56 Gb/s directdetection PolMux CAP system over a 15 km fiber link for the first time, to our best knowledge. Two-band CAP modulation with different modulated orders for each band is employed. An optical filter at the receiver is utilized to realize the polarization separation. No extra digital signal processing for polarization-dependent distortion is required. © 2015 Chinese Optics Letters.

Wang Y.,Fudan University | Wang Y.,Georgia Institute of Technology | Wang Y.,Zte United States Inc. | Wang Y.,National Engineering Research Center for Broadband Networks and Applications | And 3 more authors.
IEEE Photonics Journal | Year: 2015

The limited band of optical and electrical devices in an intensity-modulation direct detection (IM/DD) system is considered to be a major bottleneck that hinders the increase in transmission capacity. Spectrally efficient modulation formats and advanced digital signal processing are key technologies to improving the performance of IM/DD for high-speed short-reach optical systems. In this paper, we propose and experimentally demonstrate a novel Nyquist eight-level, pulse-amplitude, single-carrier modulation with frequency-domain equalization (PAM8-SCFDE). In addition, 40-GBd Nyquist PAM8-SCFDE signals can be successfully transmitted over 2-km standard single-mode fiber or 20-km large effective area fiber based on 10-G-class DAC and photodiode. Therefore, the achieved aggregate data rate is 120 Gb/s, and the measured bit error rate (BER) is under 7% pre-forward-error-correction (FEC) threshold of 3.8 × 10-3. Compared with conventional PAM8, this scheme can provide double spectral efficiency and 6-dB receiver sensitivity improvement. © 2009-2012 IEEE.

Wang Y.,Fudan University | Wang Y.,National Engineering Research Center for Broadband Networks and Applications | Tao L.,Fudan University | Huang X.,Fudan University | And 2 more authors.
IEEE Photonics Journal | Year: 2015

The light-emitting diode nonlinearity in visible light communication (VLC) systems is considered to be a major problem that deteriorates system performance. In this paper, we experimentally demonstrate a high-speed WDM CAP64 VLC system employing a Volterra series-based nonlinear equalizer to mitigate the nonlinear effect. A modified cascaded multimodulus algorithm (M-CMMA) is utilized to calculate the error function and update the weights of the nonlinear equalizer without using training symbols. An aggregate data rate of 4.5 Gb/s is successfully achieved over 2-m indoor free-space transmission with a bit error rate (BER) below the 7% forward error correction limit of 3.8× 10-3. With the Volterra nonlinear equalizer, the Q factor of the VLC system is 1.6 dB better than that without using the nonlinear equalizer, and the transmission distance is also increased by about 110 cm at the BER of 3.8× 10-3. To the best of our knowledge, this is the first time that the Volterra nonlinear equalizer is utilized for high-speed carrierless amplitude and phase (CAP) modulation-based VLC systems. © 2009-2012 IEEE.

Dai X.,Southwest University | Yang Y.,CAS Shanghai Institute of Microsystem and Information Technology | Zhang Y.,National Engineering Research Center for Broadband Networks and Applications | Gao Z.,Northumbria University | Wang H.,University of Manchester
Proceedings of the 2012 UKACC International Conference on Control, CONTROL 2012 | Year: 2012

Although the Wireless Sensor and Actuator Networks (WSANs) have many advantages than the wired networks, the nature of sharing wireless media and the complicated behavior of Media Access Control (MAC) introduce adverse impacts on the control system. In contrast to most work on networked control systems using simplified models of network induced delays, this paper considers the study the random access delay caused by a contention-based MAC scheme slotted ALOHA in WSANs. An improved fault detection observer with access delay compensation is proposed to improve the fault detection performance against the MAC delays. © 2012 IEEE.

Zhang J.,Zte United States Inc. | Zhang J.,Georgia Institute of Technology | Yu J.,Zte United States Inc. | Li F.,Zte United States Inc. | And 3 more authors.
IEEE Photonics Technology Letters | Year: 2015

We demonstrate the generation and detection of single-carrier electronic time division multiplexing 400 GE signal based on 120-GBd PDM PAM-4 signal. The signal performance is significantly improved by using our novel pre-equalization scheme. A line rate of 480-Gb/s is achieved, which enables 20% forward-error correction overheadto keep the record 400-Gb/s net information rate. © 2015 IEEE.

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