JUNE 19, 2007 -- Fujitsu Network Communications (search for Fujitsu), a supplier of IT and wireline/wireless networking solutions, is now offering integrated 40-Gbit/sec transmission capabilities for its FLASHWAVE 7500 reconfigurable optical add/drop multiplexer (ROADM). Fujitsu has developed an advanced modulation scheme and per-wavelength variable dispersion compensation (VDC) to create what it claims is the industry's first fully integrated 40-Gbit/sec ROADM that offers up to 1.6 Tbytes of capacity and a seamless upgrade of existing 10G-based DWDM networks to support 40G wavelengths.
Bill Erickson, senior vice president of planning and development at Fujitsu Network Communications, explains, "While many of our potential competitors have chosen a 40-Gbit/sec 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. By integrating 40-Gbit/sec 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."
Three new 40G units for the FLASHWAVE 7500 ROADM offer options for multiple deployment scenarios. The 40G transponder provides a full band tunable network interface and a 40G client interface, designed primarily for interconnection of core routers. The 40G muxponder combines four 10G client interfaces into a single wavelength operating at 40 Gbits/sec, which provides additional capacity expansion on constrained routes. The 40G 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 40-Gbit/sec wavelengths across existing metro/regional DWDM networks.
Optical performance requirements such as optical signal-to-noise ratio (OSNR), 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 40G DWDM transmission over existing networks, including advanced modulation techniques and per-wavelength dispersion compensation. By utilizing 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 40-Gbit/sec wavelengths. These technologies dramatically improve PMD tolerance and OSNR performance of DWDM networks, says the company, resulting in longer spans, fewer regeneration sites, and increased number of ROADM nodes per network.
The FLASHWAVE 7500 ROADM with integrated 40G capabilities will be on display this week in Booth No. 4043 at the NXTcomm 2007 conference and exhibition in Chicago (June 19-21) and in Booth No. 2647 at the SCTE Cable-Tec Expo in Orlando (June 20-22).