Liqian Wang

Flexible ring-tree TWDM network architecture for next generation optical access network

To achieve higher capacity, longer reach and flexible on-demand wavelength and timeslot provision a ring-tree time and wavelength division multiplexing (TWDM) optical access network architecture is proposed in this paper. Using active remote nodes (RNs) along fiber ring, the pressures from large split and high fiber loss are relieved and add/drop wavelengths at different RNs can be dynamically assigned. By simulations, it is verified that the architecture can provide access services to 8192 optical network units (ONUs) of 70km reach at 10Gbps, and dynamic wavelength and bandwidth allocation (DWBA) can reduce queuing delay and packet loss.

SSII cancellation in 40Gbps VSB-IMDD OFDM system based on symbol pre-distortion

We propose and experimentally demonstrate a 40Gbps downstream TD-VSB-IMDD OFDM PON scheme with symbol pre-distortion that greatly reduces the computational complexity of ONUs. 1.4dB and 2.3dB sensitivity improvement are demonstrated over 60km and 100km transmission.

Long-reach bidirectional 320 Gb/s (32×10 Gb/s) channel-reuse dense wavelength division multiplexing passive optical network employing self-wavelength managed tunable laser

Abstract. We demonstrate a channel-reuse bidirectional 10-Gb/s/λ long-reach DWDM-PON and an optical beat noise-based automatic wavelength control method for a tunable laser used in a colorless optical network unit. 100-GHz channel spacing 55- and 100-km full-duplex bidirectional 320  Gb/s (32×10  Gb/s) capacity transmissions are achieved without and with optical amplification. Transmission performance is also measured with different optical signal to Rayleigh backscattering noise ratios and different central wavelength shifts between upstream and downstream in the channel-reuse system.

Subcarrier to subcarrier intermixing interference cancellation in vestigial-sideband orthogonal frequency division multiplexing system

Abstract. The presence of vestigial-sideband optical filter, dispersion and chirp of modulator increases subcarrier to subcarrier intermixing interference (SSII), which significantly restricts transmission performance. For the first time, the iterative interference cancellation method is introduced to calculate and eliminate SSII. Furthermore, we successfully demonstrate a 40-Gbps, 16-QAM, dual drive Mach-Zehnder modulator (MZM)-based system transmission through 100-km uncompensated standard single-mode fiber. The impact of chirp on iterative algorithm is also experimentally evaluated by setting different optical phase modulation amplitudes on the two arms of the dual drive MZM.

A Novel EPON Architecture for Supporting Direct Communication Between ONUs

In the traditional EPON network, optical signal from one ONU can not reach other ONUs. So ONUs can not directly transmit packets to other ONUs .The packets must be transferred by the OLT and it consumes both upstream bandwidth and downstream bandwidth. The bandwidth utilization is low and becomes lower when there are more packets among ONUs. When the EPON network carries P2P (Peer-to-Peer) applications and VPN applications, there would be a great lot of packets among ONUs and the traditional EPON network meets the problem of low bandwidth utilization. In the worst situation the bandwidth utilization of traditional EPON only is 50 percent. This paper proposed a novel EPON architecture and a novel medium access control protocol to realize direct packets transmission between ONUs. In the proposed EPON we adopt a novel circled architecture in the splitter. Due to the circled-splitter, optical signals from an ONU can reach the other ONUs and packets could be directly transmitted between two ONUs. The traffic between two ONUs only consumes upstream bandwidth and the bandwidth cost is reduced by 50 percent. Moreover, this kind of directly transmission reduces the packets latency.

Channel-reuse bidirectional transmission with 40 Gb/s/λ downstream and 10 Gb/s/λ upstream signals in 40 km-reach WDM-PON employing remotely pumped EDFA and self wavelength managed tunable laser

We propose a channel-reuse, long-reach WDM-PON scheme and an optical beat noise-based automatic wavelength management method. A 40 km reach, channel-reuse, 40 Gb/s/λ downstream and 10 Gb/s/λ upstream signal transmission on a 100 GHz WDM grid is demonstrated.

An Equal Equivalent-channel Capacity Partition Design Method for Multi-Level Coded Modulation Scheme

We propose a partition design method for Multi-Level Coded Modulation (MLCM) based on Information Theory, by which we can obtain a labeling strategy enabling all equivalent channels of MLCM to adopt the same component code to approach the Shannon limit.

A FPGA Design Verification of Radition-Induced Single Event Effects Impact on Optical Transceiver for Space Payload System

A FPGA system is designed and implemented to test the sensitivity of different optical transceivers to “heavy ion” SEE for space payload system. The testing results show FPGA system could complete verification correctly and stably.

Method of digital signal process aided by control signal for burst-mode coherent receivers

Abstract. We propose a method of digital signal processing for a burst-mode coherent receiver, which can recover the burst data rapidly aided by a control signal. The feasibility and effectiveness of our proposed method are demonstrated in a 128 Gbps polarization division multiplexed quadrature phase shift keying modulation experiment, and the results show that the proposed method can reduce the 70% convergence time on average compared with the traditional digital signal processing without any training overhead or additional computing complexity.

A Method of Adaptive Equalization and Polarization Division De-multiplexing Aided by Control Signal for Burst-mode Coherent Receivers

We propose a method of adaptive equalization and polarization division de-multiplexing for burst-mode coherent receivers aided by control signal. 128Gbps PDM-QPSK experiment shows that the proposed method reduces 50% convergence time compared with traditional method.