ECOC 2012 summary - Part 2: Finisar
Gazettabyte completes its summary of key optical announcements at the recent ECOC show held in Amsterdam. In Part 2, Finisar's announcements are detailed.
Part 2
"The general thought with system vendors is that the more they can shrink the in-line equipment into a fewer number of slots, the more slots they have open and available for revenue-generating transceiver and transponder cards"
Rafik Ward, Finisar
Finisar showed its board-mounted parallel optics module in use within a technology demonstrator from data storage firm Xyratex, showcased what it claims is the industry's first two-slot reconfigurable optical add/ drop multiplexer (ROADM) design, unveiled its first CFP2 pluggable transceiver and announced its latest WaveShaper products.
The data storage application uses Finisar's vertical-cavity surface-emitting laser (VCSEL)-based board mounted optical assembly. The optical assembly - or optical engine - comprises 24-channels, 12 transmitters and 12 receivers.
The optical engine sits on the board and is used for such applications as chip-to-chip interconnect, optical backplanes, and dense front panels, and supports a variety of protocols. These include PCI Express, Ethernet and Infiniband as well as proprietary schemes. Indeed the only limit is the VCSEL speed. The optical engine is designed to support traffic up to 28 Gigabit-per-second (Gbps) per channel, once 28 Gigabit VCSELs become available. Finisar have already demonstrated working 28Gbps VCSELs.
The ECOC demonstration showed the optical engine in use within Xyratex's demonstrator storage system. "They are carrying traffic between internal controller cards and the traffic being carried is 12-Gig SAS [serial attached SCSI]," says Rafik Ward, vice president of marketing at Finisar.
As well as the optical engine, the demonstration included polymer waveguides from Vario-optics which connect the optical engine to a backplane connector, built by Huber + Suhner, as well as SAS silicon from LSI.
Finisar first showed the waveguide and connector technologies in a demonstration at OFC 2012. "This is an early prototype but it's a very exciting one," says Ward. "It shows all elements of the ecosystem coming together and running in a live system."
Finisar also showcased what it claims is the industry's first two-slot ROADM line card. The line card was part of a Cisco Systems' platform, according to one analyst shown the demonstration.
The company-designed card uses a high port-count wavelength-selective switch (WSS) that enables both add and drop traffic. "We have built transmit and receive into the same line card using a high port-count device," says Ward. Finisar is not detailing the exact WSS used or how the system is implemented but describes it as a flexible spectrum, 2x1x17 port line card.
The advantage of a denser ROADM line card is that it frees up slots in a system vendor's chassis. A slot can be used for either in-line equipment - WSSes and amplifiers - or terminal equipment that host the transceivers and transponders.
"It is like valuable real-estate," says Ward. "The general thought with system vendors is that the more they can shrink the in-line equipment into a fewer number of slots, the more slots they have open and available for revenue-generating transceiver and transponder cards."
The company also detailed its first CFP2 100 Gigabit optical transceiver. The CFP2 uses a single TOSA comprising four distributed feedback (DFB) lasers, a shared thermo-electric cooler and the multiplexer. The CFP2 consumes under 8W by using the DFBs and an integrated transceiver optical sub-assembly (TOSA).
The CFP2 pluggable module gains industry momentum
Finisar and Oclaro unveiled their first CFP2 optical transceiver products at the recent ECOC exhibition in Amsterdam. JDSU also announced that its ONT-100G test equipment now supports the latest 100Gbps module form factor.
Source: Oclaro
The CFP2 is the follow-on module to the CFP, supporting the IEEE 100 Gigabit Ethernet and ITU OTU4 standards. It is half the size of the CFP (see image) and typically consumes half the power. Equipment makers can increase the front-panel port density from four to eight by migrating to the CFP2.
Oclaro also announced a second-generation CFP supporting the 100GBASE-LR4 10km and OTU4 standards that reduces the power consumption from 24W to 16W. The power saving is achieved by replacing a two-chip silicon-germanium 'gearbox' IC with a single CMOS chip. The gearbox translates between the 10x10Gbps electrical interface and the 4x25Gbps signals interfacing to the optics.
The CFP2, in contrast, doesn’t include the gearbox IC.
"One of the advantages of the CFP2 module is we have a 4x25Gbps electrical interface," says Rafik Ward, vice president of marketing at Finisar. "That means that within the CFP2 module we can operate without the gearbox chip." The result is a compact, lower-power design, which is further improved by the use of optical integration.
"That 2.5x faster [interface of the CFP2] equates to about a 6x greater difficulty in signal integrity issues, microwave techniques etc"
Paul Brooks, JDSU
The transmission part of the CFP module typically comprises four externally modulated lasers (EMLs), each individually cooled. The four transmitter optical sub-assemblies (TOSAs) then interface to a four-channel optical multiplexer.
Finisar's CFP2 design uses a single TOSA holding four distributed feedback (DFB) lasers, a shared thermo-electric cooler and the multiplexer. The result of using DFBs and an integrated TOSA is that Finisar's CFP2 consumes just 8W.
Oclaro uses photonic integration on the receiver side, integrating four receiver optical sub-assemblies (ROSAs) as well as the optical demultiplexer into a single design, resulting in a 12W CFP2.
At ECOC, Oclaro demonstrated interoperability between its latest CFP and the CFP2. “It shows that the new modules will talk to existing ones,” says Robert Blum, director of product marketing for Oclaro's photonic components.
Meanwhile JDSU demonstrated its ONT-100G test set that supports the CFP2 and CFP4 MSAs.
"Initially the [test set] applications are focused on those doing the fundamental building blocks [for the 100G CFP2] – chip vendors, optical module vendors, printed circuit board developers," says Paul Brooks, director for JDSU's high speed transport test portfolio. "We will roll out more applications within the year that cover early deployment and production."
The standards-based client-side interfaces is an attractive market for test and measurement companies. For line-side optical transmission, much of the development work is proprietary such that developing a test set to serve vendors' proprietary solutions is not feasible.
The biggest engineering challenge for the CFP2 is its adoption of high-speed 25Gbps electrical interfaces. "The CFP was based on third generation, mature 10 Gig I/O [input/output]," says Brooks. "To get to cost-effective CFP2 [modules] is a very big jump: that 2.5x faster [interface] equates to about a 6x greater difficulty in signal integrity issues, microwave techniques etc."
The company says that what has been holding up the emergence of the CFP2 module has been the 104-pin connector: "The pluggable connector is the big headache," says Brooks. "The expectation is that very soon we should get some early connectors."
The test equipment also supports developers of the higher-density CFP4 module, and other form factors such as the QSFP2.
JDSU will start shipping its CFP2 test equipment in the first quarter of 2013.
Oclaro's second-generation CFP and the CFP2 transceivers are sampling, with volume production starting in early 2013.
Finisar's CFP2 LR4 product will sample in 2012 and enter volume production in 2013.
OFC announcements and market trends
More compact transceiver designs at 10, 40 and 100 Gigabit, advancements in reconfigurable optical add-drop multiplexer (ROADM) technology and parallel optical engine developments were all in evidence at this year’s OFC/NFOEC show held in Los Angeles in March.
“MSAs are designed by committee, and when you have a committee you throw away innovation and you throw away time-to-market”
Victor Krutul, Avago Technologies
Finisar said that the show was one of the busiest in recent years. “There was an increasing system-vendor presence at OFC, and there was a lot more interest from investor analysts,” says Rafik Ward, vice president of marketing at Finisar.
Ethernet interfaces
Opnext demonstrated an IEEE 100GBASE-ER4 module design at the show, the 100 Gigabit Ethernet (GbE) standard with a 40km reach. Based on the company’s CFP-based 100GBASE-LR4 10km module, the design uses a semiconductor optical amplifier (SOA) on the receive path to achieve the extended reach. The IEEE standard calls for an SOA in front of the photo-detectors for the 100GBASE-ER4 interface.
“We don’t have that [SOA] integrated yet, we are just showing the [design] feasibility,” says Jon Anderson, director of technology programme at Opnext. The extended reach interface will be used to connect IP core routers to transport system when the two platforms reside in separate facilities. Such a 40km requirement for a 100GbE interface is not common but is an important one to meet, says Anderson.
Opnext’s first-generation LR4, currently shipping, is a discrete design comprising four discrete transmitter optical sub-assemblies (TOSAs) and four receiver optical sub-assemblies (ROSAs) and an optical multiplexer and demultiplexer. The company’s next-generation design will integrate the four lasers and the optical multiplexer into a package and will be used in future more compact CFP2 and CFP4 modules.
The CFP2 module is half the size of the CFP module and the CFP4 is a quarter. In terms of maximum power, the CFP module is rated at 32W, the CFP2 12W and the CFP4 5W. “The CFP4 is a little bit wider and longer than the QSFP,” says Anderson. The first CFP2 modules are expected to become available in 2012 and the CFP4 in 2013.
System vendors are interested in the CFP4 as they want to support over one terabit of capacity on a 15-inch faceplate. Up to 16 ports can be supported –1.6Tbps – on a faceplate using the CFP4, and using a “belly-to-belly” configuration two rows of 16 ports will be possible, says Anderson.
Finisar demonstrated a distributed feedback laser (DFB) laser-based CFP module at OFC that implements the 10km 100GBASE-LR4 standard. The adoption of DFB lasers promises significant advantages compared to existing first-generation -LR4 modules that use electro-absorption modulated lasers (EMLs). “If you look at current designs, ours included, not only do they use EMLs which are significantly more expensive, but each is in its own package and has its own thermo-electric cooler,” says Ward.
Finisar’s use of DFBs means an integrated array of the lasers can be packaged and cooled using a single thermo-electric cooler, significantly reducing cost and nearly halving the power to 12W. “Now that the power [of the DFB-based] LR4 is 12W, we can place it within a CFP2 with its 25-28 Gigabit-per-second (Gbps) electrical I/O,” says Ward.
Moving to the faster input/output (I/O) compared to the CFP’s 10Gbps I/O means that that serialiser/ deserialiser (serdes) chipset can be replaced with simpler clock data recovery (CDR) circuitry. “By the time we move to the CFP4, we remove the CDRs completely,” says Ward. “It’s an un-retimed interface.” Finisar’s existing -LR4 design already uses an integrated four-photodetector array.
An early application of the 100GbE -LR4, as with the -ER4, is linking core routers with optical transport systems in operators’ central offices. Many Ethernet switch vendors have chosen to focus their early high-data efforts at 40GbE but Finisar says the move to 100GbE has started.
Finisar argues that the adoption of DFBs will ultimately prove the cost-benefits of a 4-channel 100GbE design which faces competition from the emerging 10x10 multi-source agreement (MSA). “Everything we have heard about the 10x10 [MSA] has been around cost,” says Ward. “The simple view inside Finisar is that by the time the Gen2 100GbE module that we showed at OFC gets to market, this argument [4x25Gig vs. 10x10Gig] will be a moot point.”
“40Gig is definitely still strong and healthy”
Jon Anderson, Opnext
By then the second-generation -LR4 module design will be cost competitive if not even lower cost than the 10x10 MSA. “If you look at optoelectronic components, at the end of the day what really drives cost is yield,” says Ward. “If we can get our yields of 25Gig DFBs down to a level that is similar to 10Gig DFB yields- it doesn’t have to match, just in the ballpark - then we have a solution where the 4x25Gig looks like a 4x10Gig solution and then I believe everyone will agree that 4x25Gig is a less expensive architecture.” Finisar expects the Gen2 CFP -LR4 in production by the first half of 2012.
Opnext demonstrated a 40GBASE- LR4 (40Gbps, up to 10km) standard in a QSFP+ module at OFC. Anderson says it is seeing demand for such a design from data centre operators and from switch and transport vendors.
Avago Technologies announced a 40Gbps QSFP+ module at OFC that implements the 100m IEEE 40GBASE-SR4. “It will interoperate with Avago’s SFP+ modules,” says Victor Krutul, director of marketing for the fibre optics division at Avago Technologies. The QSFP+ can interface to another QSFP+ module or to four 10Gbps SFP+ modules.
Avago also announced a proprietary mini-SFP+ design, 30% smaller than the standard SFP+ but which is electrically compatible. According to Krutul, the design came about following a request from one of its customers: “What it allows is the ability to have 64 ports on the front [panel] rather than 48.”
Did Avago consider making the mini-SFP+ design an MSA? “What we found with MSAs is that they are designed by committee, and when you have a committee you throw away innovation and you throw away time-to-market,” says Krutul.
Krutul was previously a marketing manager for Intel’s LightPeak before joining Avago over half a year ago.
“There was an increasing system-vendor presence at OFC, and there was a lot more interest from investor analysts”
Rafik Ward, Finisar.
Line-side interfaces
Opnext will be providing select customers with its 100Gbps DP-QPSK coherent module for trialling this quarter. The module has a 5-inch by 7-inch footprint and uses a 168-pin connector. “We are working to try and meet the OIF spec [with regard power consumption] which is 80W.” says Anderson. “It is challenging and it may not be met in the first generation [design].”
The company is also moving its 40Gbps 2km very short reach (VSR) transponder to support the IEEE 40GBASE-FR standard within a CFP module, dubbed the “tri-rate” design. “The 40BASE-FR has been approved, with the specification building on the ITU’s 40Gig VSR,” says Anderson. “It continues to support the [OC-768] SONET/SDH rate, it will support the new OTN ODU3 40Gbps and the intermediate 40 Gigabit Ethernet.”
Opnext and Finisar are both watching with interest the emerging 100Gbps direct detection market, an alternative to 100 Gigabit coherent aimed shorter reach metro applications.
“We certainly are watching this segment and do have an interest, but we don’t have any product plans to share at this point,” says Anderson.
“The [100Gbps] direct-detection market is very interesting,” says Ward. Coherent is not going to be the only way people will deploy 100Gbps light paths. “There will be a market for shorter reach, lower performance 100 Gigabit DWDM that will be used primarily in datacentre-to-datacentre,” he says. Tier 2 and tier 3 carriers will also be interested in the technology for use in shorter metro reaches. “There is definitely a market for that,” says Ward.
Opnext also announced its small form-factor – 3.5-inch by 4.5-inch - 40Gbps DPSK module. “With a smaller form factor, the next generation could move to a CFP type pluggable,” says Anderson. “But that is if our customers are interested in migrating to a pluggable design for DPSK and DQPSK.”
Are there signs that the advent of 100 Gigabit is affecting 40Gbps uptake? “We definitely not seeing that,” says Anderson. “We are continuing to see good solid demand for both 40G line side – DPSK and DQPSK – and a lot of pull to being this tri-rate VSR.”
Such demand is not just from China but also North Ametican carriers. “40 Gig is definitely still strong and healthy,” says Anderson “But there are some operators that are waiting to see how 100G does and approved in for major build-outs.”
At 10Gbps, Opnext also had on show a tunable TOSA for use in an XFP module, while Finisar announced an 80km, 10Gbps SFP+ module. “SFP+ has become a very successful form factor at 10Gbps,” says Ward. “All the market data I see show SFP+ leads in overall volumes deployed by a significant margin.” Its success has been achieved despite being a form factor was not designed to achieve all the 10Gbps reaches required initially. This is some achievement, says Ward, since the XFP+ form factor used for 80km has a power rating of 3.5W while the 80km SFP+ has to work within a less than 2W upper limit.
Parallel Optics
Avago detailed its main parallel optic designs: the CXP module and its two optical engine designs.
The company claims it seeing much interested from high-performance computing vendors such as IBM and Fujitsu for its CXP 120 Gigabit (12x10Gbps) parallel transceiver module. Avago is sampling the module and it will start shipping in the summer.
The company also announced the status of its embedded parallel optics devices (PODs). Such parallel optic designs offer several advantages, says Krutul. Embedding the optics on the motherboard offers greater flexibility in cooling since the traditional optics is normally at the edge of the card, furthest away from the fans. Such optics also simplify high-speed signal routing on the printed circuit board since fibre is used.
Avago offers two designs – the 8x8mm MicroPod and the 22x18mm MiniPod. The 12x10Gbps MicroPods are being used in IBM’s Blue Gene computer and Avago says it is already shipping tens of thousands of the devices a month. “The [MicroPod’s] signal pins have a very tight pitch and some of our customers find that difficult to do,” says Krutul. The MiniPod design tackles this by using the MicroPod optical engine but a more relaxed pitch. At OFC, Avago said that the MiniPod is now sampling.
Gridless ROADMs
Finisar demonstrated what it claims is the first gridless wavelength-selective switch (WSS) module at the show. A gridless ROADM supports variable channel widths beyond the fixed International Telecommunication Union's (ITU) defined spacings. Such a capability enables ROADMs to support variable channel spacings that may be required for transmission rates beyond 100Gbps: 400Gbps, 1Tbps and beyond.
“We have an increasing amount of customer interest in this [FlexGrid], and from what we can tell, there is also an increasing amount of carrier interest as well,” says Ward, adding that the company is already shipping FlexGrid WSSs to customers.
Finisar is a contributing to the ongoing ITU work to define what the grid spacings and the central channels should be for future ROADM deployments. Finisar demonstrated its FlexGrid design implementing integer increments of 12.5GHz spacing. “We could probably go down to 1GHz or even lower than that,” says Ward. “But the network management system required to manage such [fine] granularity would become incredibly complicated.” What is required for gridless is a balance between making good use of the fibre’s spectrum while ensuring the system in manageable, says Ward.