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ROADM achieves 40Gbps transmission rates

Posted: 27 Jun 2007 ?? ?Print Version ?Bookmark and Share

Keywords:reconfigurable optical add/drop mux? ROADM? mux?

Fujitsu Network Communications announced an integrated 40Gbps transmission capabilities for its popular Flashwave 7500 reconfigurable optical add/drop mux (ROADM).

Fujitsu has developed an advanced modulation scheme and per-wavelength variable dispersion compensation (VDC) to create the industry's first integrated 40Gbps ROADM solution that offers up to 1.6Tbytes of capacity and a seamless upgrade of existing 10Gbps-based dense wavelength division mux (DWDM) networks to support 40Gbps wavelengths.

"While many of our potential competitors have chosen a 40Gbps solution that requires an external shelf and alien wavelengths to work, we believe that our fully-integrated approach offers a far more compelling and manageable option for carriers," said Bill Erickson, senior VP of planning and development at Fujitsu Network Communications. "By integrating 40Gbps capability directly into the ROADM, we will achieve greater distance performance, while simplifying operations with fewer fiber jumpers, better performance monitoring, fewer spares and an overall reduction in space and power."

Enhanced networking solution
Three new 40Gbps units for the Flashwave 7500 ROADM offer options for multiple deployment scenarios. The 40Gbps transponder provides a full band tunable network interface and a 40Gbps client interface, designed primarily for interconnection of core routers. The 40Gbps muxponder combines four 10Gbps client interfaces into a single wavelength operating at 40Gbps, which provides additional capacity expansion on constrained routes. The 40Gbps regenerator unit eliminates back-to-back transponders on long spans, reducing cost and complexity. Each unit plugs directly into the existing Flashwave 7500 chassis with no changes required to support 40Gbps wavelengths across existing metro/regional DWDM networks.

Optical performance requirements such as optical SNR, chromatic dispersion, polarization mode dispersion (PMD) and spectral width become much more stringent as bit rates increase. Fujitsu has developed a number of key technologies to support 40Gbps DWDM transmission over existing networks, including advanced modulation techniques and per-wavelength dispersion compensation. By using a return to zero differential quadrature phase shift keying (RZ-DQPSK) modulation scheme and per-transponder VDC, there is no need to change dispersion compensation of existing networks when upgrading to support 40Gbps wavelengths. These technologies dramatically improve PMD tolerance and OSNR performance of DWDM networks, resulting in longer spans, fewer regeneration sites and increased number of ROADM nodes per network.

The Flashwave 7500 ROADM is widely deployed in the RBOC and MSO markets for core network consolidation, metro/regional capacity relief and triple-play service delivery. Based on a wavelength selective switch (WSS) architecture, the Flashwave 7500 ROADM can add, drop or pass-though up to 40 channels at any node with single channel granularity. Hub configurations allow up to eight-degree optical switching between multiple ring and optical (mesh) paths. The system supports network capacity to 1.6Tbps, network sizes up to 1000km and up to 24 OADM nodes per network.

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