Effdon Networks extends the 10x10 MSA to 80km

Effdon Networks has demonstrated a 100 Gigabit CFP module with an 80km reach; a claimed industry first. The company has also developed the Qbox, a 1 rack unit (1RU) extended reach platform capable of 400-800 Gigabit-per-second (Gbps) with a reach of 80-200km.

Effdon's CFP does not require the use of external DWDM multiplexing/ demultiplexing and can be added directly onto a router. Source: Effdon Networks

Available 100 Gigabit CFP modules have so far achieved 10km. Now with the Effdon module a 80km reach has been demonstrated that uses 10Gbps optics and no specialist silicon.

Effdon's design is based on the 10x10 MSA (multi-source agreement). "We have managed to resolve the technology barriers - using several techniques - to get to 80km," says Eitan Efron, CEO of Effdon Networks.

There is no 100 Gigabit standard for 80km. The IEEE has two 100 Gigabit standards: the 10km long reach 100GBASE-LR4 and the 40km extended reach 100GBASE-ER4.

Meanwhile, the 100 Gigabit 10x10 MSA based on arrays of 10, 10 Gigabit lasers and detectors, has three defined reaches: 2km, 10km and 40km. At the recent OFC/NFOEC exhibition, Oplink Communication and hybrid integration specialist, Kaiam, showed the 10x10 MSA CFP achieving 40km.

Effdon has not detailed how it has achieved 80km but says its designers have a systems background. "All the software that you need for managing wavelength-division multiplexing (WDM) systems is in our device," says Efron. "Basically we have built a system in a module." 

These system elements include component expertise and algorithmic know-how. "Algorithms and software; this is the main IP of the company," says Efron. "We are using 40km components and we are getting 80km."

100 Gigabit landscape 

Efron says that while there are alternative designs for 100 Gigabit transmission at 80km or more, each has challenges.

A 100Gbps coherent design achieves far greater reaches but is costly and requires a digital signal processor (DSP) receiver ASIC that consumes tens of watts. No coherent design has yet been implemented using a pluggable module.

Alternative CFP-based 100Gbps direct-detection designs based on a 4x28Gbps architecture exist. But their 28Gbps lanes experience greater dispersion that make achieving 80km a challenge.

MultiPhy's MP1100Q DSP chip counters dispersion. The chip used in a CFP module achieves a 55km point-to-point reach using on-off keying and 800km for dense WDM metro networks using duo-binary modulation.

Finisar and Oclaro also offer 100Gbps direct detection CFP modules for metro dense WDM using duo-binary modulation but without a receiver DSP. ADVA Optical Networking is one system vendor that has adopted such 100Gbps direct-detect modules.  Another company developing a 4x28Gbps direct detect module is Oplink Communications.

But Effdon points out that its point-to-point CFP achieves 80km without using an external DWDM multiplexer and demultiplexer - the multiplexing/demultiplexing of the wavelengths is done within the CFP - or external amplification and dispersion compensation. As a result, the CFP plugs straight into IP routers and data centre switches.

"What they [data centre managers] want is what they have today at 10 Gig: ZR [80km] optical transceivers," says Efron

Market demand

"We see a lot of demand for this [80km] solution," says Efron. The design, based on 10 Gigabit optics, has the advantage of using mature high volume components while 25Gbps component technology is newer and available in far lower volumes.

"This [cost reduction associated with volume] will continue; we see 10 Gig lasers going into servers, base stations, data centre switches and next generation PON," says Efron. "Ten Gigabit optical components will remain in higher volume than 25 Gig in the coming years."   

The 10x10 MSA CFP design can also be used to aggregate multiple 10 Gig signals in data centre and access networks. This is an emerging application and is not straightforward for the more compact, 4x25Gbps modules as they require a gearbox lane-translation IC.   

Reach extension

Effdon Networks' Qbox platform provides data centre managers with 400-800Gbps capacity while offering a reach up to 200km. The box is used with data centre equipment that support CXP or QSFP modules but not the CFP.  The 1RU box thus takes interfaces with a reach of several tens of meters to deliver extended transmission.

Qbox supports eight client-side ports - either 40 or 100 Gbps - and four line-facing ports at speeds of 100Gbps or 200Gbps for a reach of 80 to 200km. In future, the platform will deliver 400Gbps line speeds, says Efron.

Samples of the 80km CFP and Qbox are available for selected customers, says Effdon, while general availability of the products will start in the fourth quarter of 2013.