Fujitsu adds coherent 40G to FLASHWAVE 7500 ROADM

MARCH 18, 2010 By Stephen Hardy – While several system and module vendors are working on dual-polarization quadrature phase-shift keying (DP-QPSK) with coherent detection for 100 Gbps, Fujitsu has decided to offer the technology commercially at 40 Gbps this year.

MARCH 18, 2010 By Stephen Hardy – While several system and module vendors are working on dual-polarization quadrature phase-shift keying (DP-QPSK) with coherent detection for 100 Gbps, Fujitsu has decided to offer the technology commercially at 40 Gbps this year. The company has announced three 40G cards based on the advanced modulation format and receiver technology for its FLASHWAVE 7500 Reconfigurable Optical Add/Drop Multiplexer (ROADM).

Fujitsu Network Communications currently offers 40-Gbps capabilities on the FLASHWAVE 7500 based on adaptive differential phase-shift keying (ADPSK), says Randy Eisenach, WDM product marketing director at the company. The ADPSK 40G capabilities will continue to be offered, in part due to its lower cost. “It’s not a huge difference, but it’s significant enough that customers would notice,” he says of the new technology’s higher price tag.

However, customers will receive better performance for the additional money. Eisenach says the DP-QPSK/coherent detection pairing offers an optical signal-to-noise ratio (OSNR) improvement of about 2-3 dB, plus improved resistance to the effects of polarization-mode dispersion (PMD). The fact that the technology would obviate the need for separate dispersion compensation on links with high-PMD fiber could mean an overall savings network-wide, Eisenach notes.

That said, the company is still pondering whether to apply the same technology to the FLASHWAVE 9500 Packet Optical Networking Platform or wait until it graduates to 100 Gbps, Eisenach reveals. Fujitsu likely will use a module-based strategy for such 100G capabilities, Eisenach says, rather than a handmade approach. The company is not saying where the 40G DP-QPSK technology originated.

However, current FLASHWAVE 7500 customers need the performance of coherent-based technology at 40G now, Eisenach says. To that end, the company will offer three cards:

  • the FC9682QUC2 transponder
  • the FC9682QMC2 4:1 muxponder
  • the FC9682QRC2 regenerator


The double-wide cards will be available for lab and other testing in June. General availability is scheduled for this September. Eisenach says the muxponder has received the most interest so far.

At least one analyst expects sees such interest as a reflection of the overall 40G market. “The market for 40G transport gear surpassed $500 million in 2009 as carriers around the globe embraced the technology,” Ron Kline, principal analyst of network infrastructure at Ovum, was quoted as saying in Fujitsu’s press release. “The latest Fujitsu 40G products respond to evolving and growing market needs for systems with higher tolerance to dispersion while at the same time shortening the 100G developmental cycle. We expect the market for 40G to double this year and exceed $3 billion by 2014.”

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