Bert Basch

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.

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.

Multi-rate (111-Gb/s, 2×43-Gb/s, and 8×10.7-Gb/s) transmission at 50-GHz channel spacing over 1040-km field-deployed fiber

111-Gb/s transmission combined with 2 times 43-Gb/s and 8 times 10.7-Gb/s on a 50-GHz grid over 1,040-km field fiber and two ROADMs is demonstrated, showing the feasibility of 100G overlaying existing 10G/40G commercial systems.

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.

111-Gb/s Transmission Over 1040-km Field-Deployed Fiber With 10G/40G Neighbors

We demonstrate transmission of a 111-Gb/s coherent polarization-multiplexed return-to-zero differential quadrature phase-shift keying signal over 1040-km field-deployed fiber together with different types of neighboring channels, and with a cascade of 50-GHz reconfigerable optical add-drop multiplexers. Our transmission experiment proves the feasibility of transmitting a 111-Gb/s phase-modulated channel with 10 times 10.7-Gb/s on-off keying neighboring channels on a 50-GHz grid, despite the presence of strong cross-phase modulation.

Transmission of 107-Gb/s DQPSK over Verizon 504-km Commercial LambdaXtreme® Transport System

A 107-Gb/s field trial was conducted on a traffic carrying long-haul LambdaXtreme® transport platform over an active 504-km Verizon route in Florida thus proving upgradeability to 100 G of the Alcatel-Lucent 50-GHz spaced ULH DWDM system.

The value of multiple degree ROADMs on metropolitan network economics

We compare alternative ROADM network architectures through a study based on real LEC data. We show that optimally deployed higher-degree ROADMs with optical bypass and grooming can simultaneously reduce the cost of both the optical and SONET layers.

Dejittering in the transport of MPEG-2 and MPEG-4 video

Abstract. When multimedia information is transported over a packet-switched network, the quality of presentation can be degraded due to network delay variation or jitter. This paper presents a dejittering scheme that can be used in the transport of MPEG-4 and MPEG-2 video to absorb any introduced network jitter, thus preserving the presentation quality of transported media streams. The dejittering scheme is based on the statistical approximation of delay variation in the arrival times of video packets carrying encoded clock reference values and a filtering and re-stamping mechanism. In addition, a brief overview of the MPEG-4 system is presented.

Continuous Phase Modulation for Fiber-Optic Links

Advances in photonics, silicon electronics and digital signal processing (DSP) have converged to enable highly efficient transmission across fiber optic channels. Single wavelength data rates of 112 Gb/s are sought for wide deployment based on QPSK transmission, coherent detection, and digital demodulation. Here we examine continuous phase modulation (CPM) as a means to enhance performance and reach of coherent optical links. We quantify the robustness of the constant amplitude CPM format to spectral filtering and nonlinearities in comparison to QPSK. The challenges of generating and receiving the CPM waveform are considered and a novel CPM transmitter architecture is proposed.

Field trial of 107-Gb/s channel carrying live video traffic over 504 km in-service DWDM route

A 107-Gbps field trial carrying live HDTV traffic over a 504-km in-service DWDM route, proving commercial systems designed for 10G/40G can be upgraded to 100G without impacting existing active channels.