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Entries in PAM-4 (21)

Friday
Oct202017

The many paths to 400 gigabits

The race is on to deliver 400-gigabit optical interfaces in time for the next-generation of data centre switches expected in late 2018.

The industry largely agrees that a four-wavelength 400-gigabit optical interface is most desirable yet alternative designs are also being developed.

Optical module makers must consider such factors as technical risk, time-to-market and cost when choosing which design to back.

Rafik Ward, FinisarUntil now, the industry has sought a consensus on interfaces, making use of such standards bodies as the IEEE to serve the telecom operators.

Now, the volumes of modules used by the internet giants are such that they dictate their own solutions. And the business case for module makers is sufficiently attractive that they are willing to comply.

Another challenge at 400 gigabits is that there is no consensus regarding what pluggable form factor to use. 

“There is probably more technical risk in 400 gigabits than any of the historical data-rate jumps we have seen,” says Rafik Ward, vice president of marketing at Finisar.

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Monday
Oct092017

Oclaro’s 400-gigabit plans

Adam Carter, Oclaro’s chief commercial officer, discusses the company’s 400-gigabit and higher-speed coherent optical transmission plans and the 400-gigabit client-side pluggable opportunity.    

Oclaro showcased its first coherent module that uses Ciena’s WaveLogic Ai digital signal processor at the ECOC show held recently in Gothenburg.

Adam CarterOclaro is one of three optical module makers, the others being Lumentum and NeoPhotonics, that signed an agreement with Ciena earlier this year to use the system vendor’s DSP technology and know-how to bring coherent modules to market. The first product resulting from the collaboration is a 5x7-inch board-mounted module that supports 400-gigabits on a single-wavelength.   

The first WaveLogic Ai-based modules are already being tested at several of Oclaro’s customers’ labs. “They [the module samples] are very preliminary,” says Adam Carter, the chief commercial officer at Oclaro. “The really important timeframe is when we get towards the new year because then we will have beta samples.”

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Monday
Sep252017

The CWDM8 MSA avoids PAM-4 to fast-track 400G  

Another multi-source agreement (MSA) group has been created to speed up the market introduction of 400-gigabit client-side optical interfaces.

The CWDM8 MSA is described by its founding members as a pragmatic approach to provide 400-gigabit modules in time for the emergence of next-generation switches next year. The CWDM8 MSA was announced at the ECOC show held in Gothenburg last week.

Robert BlumThe eight-wavelength coarse wavelength-division multiplexing (CWDM) MSA is being promoted as a low-cost alternative to the IEEE 803.3bs 400 Gigabit Ethernet Task Force’s 400-gigabit eight-wavelength specifications, and less risky than the newly launched 100G Lambda MSA specifications based on four 100-gigabit wavelengths for 400 gigabit.

“The 100G Lambda has merits and we are also part of that MSA,” says Robert Blum, director of strategic marketing and business development at Intel’s silicon photonics product division. “We just feel the time to get to 100-gigabit-per-lambda is really when you get to 800 Gigabit Ethernet.”

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Sunday
Sep242017

MultiPhy unveils 100G single-wavelength PAM-4 chip

A chip to enable 100-gigabit single-wavelength client-side optical modules has been unveiled by MultiPhy. The 100-gigabit 4-level pulse amplitude modulation (PAM-4) circuit will also be a key building block for 400 Gigabit Ethernet interfaces that use four wavelengths.

Source: MultiPhy

Dubbed the MPF3101, the 100-gigabit physical layer (PHY) chip is aimed at such applications as connecting switches within data centres and for 5G cloud radio access network (CRAN).

“The chip has already been sent out to customers and we are heading towards market introductions,” says Avi Shabtai, CEO of MultiPhy.

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Tuesday
Sep052017

Inphi unveils a second 400G PAM-4 IC family

Inphi has announced the Vega family of 4-level, pulse-amplitude modulation (PAM-4) chips for 400-gigabit interfaces.

The 16nm CMOS Vega IC family is designed for enterprise line cards and is Inphi’s second family of 400-gigabit chips that support eight lanes of 50-gigabit PAM-4.

Its first 8x50-gigabit family, dubbed Polaris, is used within 400-gigabit optical modules and was announced at the OFC show held in Los Angeles in March.

“Polaris is a stripped-down low-power DSP targeted at optical module applications,” says Siddharth Sheth, senior vice president, networking interconnect at Inphi (pictured). “Vega, also eight by 50-gigabits, is aimed at enterprise OEMs for their line-card retimer and gearbox applications.”  

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Sunday
Aug202017

SFP-DD: Turning the SFP into a 100-gigabit module

Part 2: New optical transceiver MSA

An industry initiative has started to quadruple the data rate of the SFP, the smallest of the pluggable optical modules. The Small Form Factor Pluggable – Double Density (SFP-DD) is being designed to support 100 gigabits by doubling the SFP’s electrical lanes from one to two and doubling their speed.

Scott SommersThe new multi-source agreement (MSA), to be completed during 2018, will be rated at 3.5W; the same power envelope as the current 100-gigabit QSFP module, even though the SFP-DD is expected to be 2.5x smaller in size.

The front panel of a 1-rack-unit box will be able to support up to 96 SFP-DD modules, a total capacity of 9.6 terabits. 

The SFP-DD is adopting a similar philosophy as that being used for the 400-gigabit QSFP-DD MSA: an SFP-DD port will support legacy SFPs modules - the 25-gigabit SFP28 and 10-gigabit SFP - just as the QSFP-DD will be backward compatible with existing QSFP modules.

“Time and time again we have heard with the QSFP-DD that plugging in legacy modules is a key benefit of that technology,” says Scott Sommers, group product manager at Molex and the chair of the new SFP-DD MSA. Sommers is also a co-chair of the QSFP-DD MSA.

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Tuesday
Sep202016

Ranovus shows 200 gigabit direct detection at ECOC

Ranovus has announced it first direct-detection optical products for applications including data centre interconnect.


Saeid AramidehThe start-up has announced two products to coincide with this week’s ECOC show being held in Dusseldorf, Germany.

One product is a 200 gigabit-per-second (Gbps) dense wavelength-division multiplexing (WDM) CFP2 pluggable optical module that spans distances up to 130km. Ranovus will also sell the 200Gbps transmitter and receiver optical engines that can be integrated by vendors onto a host line card. 

The dense WDM direct-detection solution from Ranovus is being positioned as a cheaper, lower-power alternative to coherent optics used for high-capacity metro and long-haul optical transport. Using such technology, service providers can link their data centre buildings distributed across a metro area. 

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