Hongxiang Wang

Simultaneous multichannel wavelength multicasting and XOR logic gate multicasting for three DPSK signals based on four-wave mixing in quantum-dot semiconductor optical amplifier

In this paper, we experimentally demonstrate simultaneous multichannel wavelength multicasting (MWM) and exclusive-OR logic gate multicasting (XOR-LGM) for three 10Gbps non-return-to-zero differential phase-shift-keying (NRZ-DPSK) signals in quantum-dot semiconductor optical amplifier (QD-SOA) by exploiting the four-wave mixing (FWM) process. No additional pump is needed in the scheme. Through the interaction of the input three 10Gbps DPSK signal lights in QD-SOA, each channel is successfully multicasted to three wavelengths (1-to-3 for each), totally 3-to-9 MWM, and at the same time, three-output XOR-LGM is obtained at three different wavelengths. All the new generated channels are with a power penalty less than 1.2dB at a BER of 10(-9). Degenerate and non-degenerate FWM components are fully used in the experiment for data and logic multicasting.

Nonlinear decision boundary created by a machine learning-based classifier to mitigate nonlinear phase noise

A machine learning-based classifier, namely SVM, is introduced to create the nonlinear decision boundary in M-ary PSK-based coherent optical system to mitigate NLPN. The maximum transmission distance and LPRD tolerance are improved by 480 km and 3.3 dBm for 8PSK.

The first experimental demonstration of a DREAM-based large-scale optical transport network with 1000 control plane nodes

A scalable framework named Dual Routing Engine Architecture in Multi-layer, multi-domain and multi-constraints scenarios (DREAM) is proposed for the routing issue in large-scale dynamic optical networks. DREAM-based optical transport network testbed with 1000 control plane nodes and multi-terabit per second ODUk electrical cross-connects is first experimentally demonstrated. Two proposed routing schemes, i.e. DRE Forward Path Computation (DRE-FPC) and Hierarchical DRE Backward Recursive PCE-based Computation (HDRE-BRPC) are deployed and validated on the testbed, compared with traditional hierarchical routing (HR) scheme. Experimental results show the good performance of DREAM.

Multifunctional switching unit for add/drop, wavelength conversion, format conversion, and WDM multicast based on bidirectional LCoS and SOA-loop architecture

We propose a multifunctional optical switching unit based on the bidirectional liquid crystal on silicon (LCoS) and semiconductor optical amplifier (SOA) architecture. Add/drop, wavelength conversion, format conversion, and WDM multicast are experimentally demonstrated. Due to the bidirectional characteristic, the LCoS device cannot only multiplex the input signals, but also de-multiplex the converted signals. Dual-channel wavelength conversion and format conversion from 2 × 25Gbps differential quadrature phase-shift-keying (DQPSK) to 2 × 12.5Gbps differential phase-shift-keying (DPSK) based on four-wave mixing (FWM) in SOA is obtained with only one pump. One-to-six WDM multicast of 25Gbps DQPSK signals with two pumps is also achieved. All of the multicast channels are with a power penalty less than 1.1 dB at FEC threshold of 3.8 × 10⁻³.

Early traffic identification using Bayesian networks

Port-based or payload-based analysis is becoming difficult for accurate traffic identification when many applications use dynamic port numbers and encryption to avoid detection. In this paper we present an approach for online traffic classification relying on the observation of the first n packets of a flow. The packet size and inter-arrival times of the individual packets, rather than the statistic features, are chosen as identification parameters. We use labeled data set as training set to construct a Naïve Bayes classifier and use the real discretized conditional probability instead of Gaussian distribution. Two real data sets collected in the campus networks are used to evaluate the proposed approach and the effectiveness is proved. The results also indicate that this approach is not sensitive to the prior probability estimation in most cases, and that packet sizes are more efficient than the inter-arrival times although both of them are important.

Flexible and re-configurable optical three-input XOR logic gate of phase-modulated signals with multicast functionality for potential application in optical physical-layer network coding

Optical logic gate, especially exclusive-or (XOR) gate, plays important role in accomplishing photonic computing and various network functionalities in future optical networks. On the other hand, optical multicast is another indispensable functionality to efficiently deliver information in optical networks. In this paper, for the first time, we propose and experimentally demonstrate a flexible optical three-input XOR gate scheme for multiple input phase-modulated signals with a 1-to-2 multicast functionality for each XOR operation using four-wave mixing (FWM) effect in single piece of highly-nonlinear fiber (HNLF). Through FWM in HNLF, all of the possible XOR operations among input signals could be simultaneously realized by sharing a single piece of HNLF. By selecting the obtained XOR components using a followed wavelength selective component, the number of XOR gates and the participant light in XOR operations could be flexibly configured. The re-configurability of the proposed XOR gate and the function integration of the optical logic gate and multicast in single device offer the flexibility in network design and improve the network efficiency. We experimentally demonstrate flexible 3-input XOR gate for four 10-Gbaud binary phase-shift keying signals with a multicast scale of 2. Error-free operations for the obtained XOR results are achieved. Potential application of the integrated XOR and multicast function in network coding is also discussed.

Optical Network Node Supporting One-to-Six WDM Multicasting of QPSK Signals

The capability of multicast directly in the optical domain at the routing nodes is a target for energy saving, fast service provisioning, and effective network resource utilization. An optical network node architecture supporting wavelength conversion, unicast, and multicast is presented and a shared multicast/wavelength conversion module is designed in the intermediate node. Wavelength conversion and one-to-six WDM multicast of 25-Gb/s QPSK signals based on four-wave mixing are experimentally demonstrated using a semiconductor optical amplifier with only two pumps. All six multicast signals achieve error-free performance with a power penalty <;4.3 dB.

Research on performance of multicasting in optical packet switched networks

Different multicasting schemes in optical packet switched networks are discussed, including the parallel mode, serial mode, and hybrid mode multicasting schemes. Simulated modeling technique is applied to compare the network-level performance of the three multicasting schemes. A conclusion can be drawn from the results that since the hybrid-mode multicasting scheme can increase the multicast success ratio and reduce the packet retransmission times compared with the other two schemes, it is the best choice for delivering multicasting sessions in the optical packet switched networks.

A minimum wavelength tuning scheme for dynamic wavelength assignment in TWDM-PON

Time and wavelength division multiplexed passive optical networks (TWDM-PONs) have been chosen by the Full Service Access Network (FASN) group as the primary solution for next-generation passive optical network stage-2(NG-PON2). The key components in TWDM-PON are the tunable receivers and tunable transmitters at the ONU. However, most of the dynamic wavelength assignment algorithms are not considering the tuning time. In reality, wavelength tuning will limit channel utilization and increase packet delay. In this paper, we proposed a minimum wavelength tuning (MWT) scheme which is reducing the frequency of wavelength tuning. Simulation results show that MWT scheme can effectively reduce packet delay and improve the channel utilization.

LP-DWBA: A DWBA algorithm based on linear prediction in TWDM-PON

A dynamic wavelength and bandwidth allocation (DWBA) algorithm based on linear prediction( LP-DWBA) to schedule resources in TWDM-PON is proposed. Simulation results show that LP-DWBA can reduce the average end-to-end delay of networks greatly compared with the existing schemes.