Lei Zong

Study on wavelength cross-connect realized with wavelength selective switches

A novel structure for wavelength cross-connect (WXC) is proposed using the wavelength selective switch (WSS) devices. A 4/spl times/4 WXC node is realized and tested. The key technologies for the WSS based WXC node are also discussed.

A Novel Tunable DeMUX/MUX Solution for WSS-Based ROADM and WXC Nodes

We introduce the applications and technologies of tunable demultiplexers/multiplexers (DeMUX/MUX) in wavelength division multiplexing (WDM) networks. We also propose a novel solution using fixed waveband filters to achieve similar provisioning flexibility and reduced control complexity.

A Novel WDM-PON Architecture with Centralized Lightwaves in the OLT for Providing Triple Play Services

A novel WDM-PON architecture with centralized lightwave source in the optical line terminal (OLT) for providing triple play services has been proposed and demonstrated. Triple play service provision with 2.5 Gbit/s video signals, 10 Gbit/s downstream signals, and 10 Gbit/s upstream signals per channel has been successfully realized.

Optical tunable asymmetric interleaver

A novel optical tunable asymmetric interleaver is demonstrated. It consists of two symmetric interleaves with wavelength shifting capability in series. It can deliver continuous tunable interleaving ratios for WDM applications, particularly for 10 G+40 G network upgrade.

A Novel Protection Scheme for WDM-PONs Using Waveband Filters

We propose and demonstrate a novel structure for the remote node and optical network unit of the WDM-PONs using waveband filters. We also propose a new protection scheme for PON distribution fiber failures.

Next generation multi-service optical networks

Current optical transport networks are based on non-transparent SONET/SDH technology. Wavelength multiplexed systems (WDM) modulate optical signals with SONET/SDH digital formats at 2.5 and 10Gb/s rates. Transparent Optical Networks have been actively researched as a way to make optical transport independent from the electronic signals transmitted. In this article, we review recent developments in optical components that facilitate a flexible spectrum usage of DWDM systems. In addition, we discuss emerging optical transport services and how they can be best served by a state-of-the-art transport network.

Testbed for ROADM and WXC based metro WDM networks

A testbed for metro wavelength division multiplexing (WDM) network is realized and tested. The testbed contains a reconfigurable optical add/drop multiplexer (ROADM) node, a 2x2 wavelength cross-connect (WXC) node, and two interconnected two-fiber bidirectional path protected switching ring networks (TF-BPSR). Both the ROADM and WXC node are bidirectional nodes, so they can select channels from the working and the protection ring networks simultaneously, and they support both protected and unprotected services. The ROADM node uses a flexible band tunable filter (FBTF) to drop a waveband from the input WDM signals and send the express channels directly to the output port. As a result, the physical impairment accumulated on the express channels can be minimized. It also has a modular structure, so additional modules can be cascaded to expand the capacity and functionality of the node without any interruption to current services. The WXC node is realized with interconnected ROADM modules that are comprised of wavelength selective switches (WSSes). Arbitrary wavelength or wavelength sets can be either dropped in the node or cross-connected in a non-blocking manner. Multiple services, such as OC-48 and OC-192 SONET signals, gigabit Ethernet streams carrying interactive movie signals, and live video broadcasting services, are carried in the network, dropped in the ROADM and WXC node, and switched between the two ring networks. The testbed is controlled by a websever based network management system that facilitates remote control and monitoring. Experiments demonstrate that the performance of the nodes and the testbed meets the requirement of the services.

8×11.5-Gb/s OFDM Transmission over 1000km SSMF using Conventional DFB Lasers and Direct-Detection

We show 8 × 11.5-Gb/s (10-Gb/s after coding) optical OFDM transmission over 1000 km SSMF with conventional DFB lasers and direct-detection. Compared with the coherent-detection using ECL lasers, DFB lasers and direct-detection can significantly reduce the system complexity and cost.

Optically Labeled 100Gbit/s packet signals passing through 8 straight-line OWSS nodes and 240km fiber

We have experimentally demonstrated optically labeled 100 Gbit/s packet signals passing through 8 straight-line OWSS nodes and 240 km transmission fiber for the first time. The BER performance for the optical packet signals after transmission and switching has been evaluated.

State-Based Algorithm for Power Stability Control in Transparent WDM Networks

This paper analyzes power fluctuation caused by interaction of fiber cut, add/drop operation, EDFA transients and ROADM attenuation adjustment in WDM networks. A state-based power control algorithm is proposed and tested in our simulation system.