Roman Egorov

Flexible architectures for optical transport nodes and networks

Flexibility to support mesh topologies, dynamic capacity allocation, and automated network control and light path setup are key elements in the design of next-generation optical transport networks. To realize these capabilities, reconfigurable optical add/drop multiplexers with dynamic add/drop structures, embedded control planes, and lightpath characterization are required. This article presents the architectures and various ROADM implementations including colorless, directionless, and contentionless add/drop structures. The effect of scaling bit rates beyond 100 Gb/s on ROADM architectures is reviewed including providing variable channel bandwidth depending on bit rate. Automated provisioning and restoration using the GMPLS control plane and optical measurement approaches for lightpaths are also discussed.

Architectural tradeoffs for reconfigurable dense wavelength-division multiplexing systems

Advances in optical technology now allow practical reconfigurable wavelength networks to be constructed. These networks use wavelength-switching components to dynamically route wavelengths, and provide a level of flexibility and scalability previously not possible. Other components such as low-noise optical amplifiers, electronic dispersion compensators, and advanced modulation techniques simplify system operation, increase capacity, and extend reach. From an application perspective, the architecture of optical transport networks is evolving based on the requirement to support a higher bandwidth access infrastructure. The network architecture also needs to provide the flexibility to incrementally expand on the basis of customer demand and to provide key features such as optical broadcast to lower the cost of video services. The development of new architectures for optical transport networks and how these networks are influenced by critical system parameters and emerging component technologies is reviewed

Robust compression and transmission of MPEG-4 video

This paper discusses issues related to the delivery of MPEG-4 video over the Internet and wireless channels. MPEG-4s built-in error resilience capabilities such as flexible re-synchronization markers, data partitioning, header protection, reversible VLCs, and forced intra-frame refresh are described. Methods for using these techniques to build a “smart” network decoder are discussed, and the decoders video quality is measured for various channel error conditions. The effectiveness and overheads of the various error resilience techniques are compared using both peak signal-to-noise ratio measurements and expert viewing. The use of forward error correcting strategies and the effects of packet sizes and boundaries on video quality are also examined.

Transmission of MPEG-2 video streams over ATM

Experiments investigated the relationship between MPEG video quality and ATM network performance. Preliminary results reveal the effects of network impairments on video quality for MPEG-2 transport streams delivered over ATM. The issues in mapping variable-rate MPEG to ATM are also examined, including the trade-off between bandwidth savings and video quality.

Next Generation ROADM architecture and design

Next Generation ROADM design that supports Colorless Directionless and Contentionless (CDC) architecture and supports Flexible grid is described. Benefits of CDC Flexible grid ROADM architecture are discussed. Tradeoffs between different aspects of design are presented.

Real-time 127-Gb/s coherent PM-QPSK transmission over 1000km NDSF with >10 cascaded 50GHz ROADMs

This paper describes experimental demonstration of 50GHz ROADM tolerance for a realtime, single-carrier, 127-Gb/s coherent PM-QPSK system. 10 WSSs are cascaded over 1000km NDSF and <0.5dB OSNR penalty is measured for the worst case. Cascading limit is also predicted.

DWDM system architecture and design trade-offs

The architecture of metropolitan transport equipment is evolving based on the changing requirements needed to support a high bandwidth access infrastructure that is video rich and the availability of a new generation of optical components including wavelength switches

Experimental study of intra- vs. inter-superchannel spectral equalization in flexible grid systems

Benefits of intra-superchannel spectral-equalization are demonstrated in a production 8Tbps system. ~1.2dB OSNR improvement and ~4.5dB reduction in power-spread is measured relative to inter-superchannel equalization. Tradeoff between OSNR and nonlinearity dictates the net reach improvement.

Optimizing Transport Systems to Integrate TDM and Packet Services

Transport elements must evolve to seamlessly integrate TDM and packet services into a single platform. This integration is best achieved using a hybrid switch that is capable of switching both TDM and packet flows.

DWDM Systems and Mini ROADM applications

We examine the mini-ROADM application based on new type of WSS component. Mini-ROADM application allows optimization between the cost and functionality that is important to widespread deployment of dynamically reconfigurable optical mesh network.