Transmode adopts 100 Gigabit coherent CFPs

Transmode has detailed line cards that bring 100 Gigabit coherent CFP optical modules to its packet optical transport platforms. 

We can be quicker to market when newer DSP-based CFPs appear

Jon Baldry

"We believe we are the first to market with line-side coherent CFPs, bringing pluggable line-side optics to a WDM portfolio," says Jon Baldry, technical marketing director at Transmode. Baldry says that other system vendors already support non-coherent CFP modules on their line cards and that further vendor announcements using coherent CFPs are to be expected.       

The Swedish system vendor announced three line cards: a 100 Gig transponder, a 100 Gig muxponder and what it calls its Ethernet muxponder (EMXP) card. The first two cards support wavelength division multiplexing (WDM) Layer 1 transport: the 100 Gig transponder card supports two 100 Gig CFP modules while the 100 Gig muxponder supports 10x10 Gig ports and a CFP.

The third card, the EMXP220/IIe, has a capacity of 220 Gig: 12x10 Gigabit Ethernet ports and the CFP, with all 13 ports supporting optional Optical Transport Network (OTN) framing. "You can think of it as a Layer 2 switch on a card with 13 embedded transponders," says Baldry.  The three cards each take up two line card slots.   

Transmode's platforms are used for metro and metro regional networks. Metro has more demanding cost, space and power efficiency requirements than long distance core networks. "The move that the whole industry is taking to CFP or pluggable-based optics is a big step forward [in meeting metro's requirements]," says Baldry. 

The line cards will be used with Transmode's metro edge TM-Series packet optical family that is suited for applications such as mobile backhaul and business services. "Within packet-optical networks, we can do customer premise Gigabit Ethernet all the way through to 100 Gig handover to the core on the same family of cards running the same Layer 2 software," says Baldry. Transmode believes this capability is unique in the industry.

The TM-3000 chassis is 11 rack units (RU) high and can hold eight double-slot cards, for a total of 800 Gig CFP line side capacity.   

Source: Transmode

100 Gig coherent modules

Transmode is talking to several 100 Gig coherent CFP module makers. The company will use multiple suppliers but says it is currently working with one manufacturer whose product is closer to market.

Acacia Communications announced the first CFP module late last year and other module makers are expected to follow at the upcoming OFC show in March 2014.

The roadmap of the CFP modules envisages the CFP to be followed by the smaller CFP2 and  smaller still CFP4. For the CFP2 and CFP4, the coherent digital signal processor (DSP) ASIC is expected to be external to the module's optics, residing on the line card instead. The 100 Gig CFP, however, integrates the DSP-ASIC within the module and this approach is favoured by Transmode.     

"We can be quicker to market when newer DSP-based CFPs appear; today we can do 800km and in the future that will go to a longer reach or lower power consumption," says Baldry. "Also, the same port can take a coherent CFP or a 100BASE-SR4 or -LR4 CFP without having the cost burden of a DSP on the card whether it is needed or not." 

The company also points out that by using the integrated CFP it can choose from all the coherent designs available whereas modules that separate the optics and DSP-ASIC will inevitably offer a more limited choice. 

There are also 100 Gigabit direct detection CFPs from the likes of Finisar and Oplink Communications and Transmode's cards would support such a CFP module. But for now the company says its main interest is in coherent.

"One key requirement for anything we deploy is that it works with the existing optical infrastructure," says Baldry. "One difference between 100 Gig metro and long haul is that a lot of the long distance 100 Gig is new build, whereas the metro  will require 100 Gig over existing infrastructure and coherent works very nicely with the existing design rules and existing 10 Gig networks."   

The 100 Gig transponder card consumes 75W, with the coherent CFP accounting for 30W of the total. The card can be used for signal regeneration, hosting two 100 Gig coherent CFPs rather than the more typical arrangement of a client-side and a line-side CFP. The card's power consumption exceeds 75W, however, when two coherent CFPs are used.

The 100 Gig transponder and Ethernet muxponder will be available in the second quarter of 2014, says Transmode, while the 100 Gig muxponder card will follow early in the third quarter of the year.