ECOC 2012 summary - Part 1: Oclaro
Gazettabyte completes its summary of key optical announcements at the recent ECOC show held in Amsterdam. Oclaro's announcements detailed here are followed by those of Finisar and NeoPhotonics.
Part 1: Oclaro
"Networks are getting more complex and you need automation so that they are more foolproof and more efficient operationally"
Per Hansen, Oclaro
Oclaro made several announcements at ECOC included an 8-port flexible-grid optical channel monitor, a new small form factor pump laser MSA and its first CFP2 module. The company also gave an update regarding its 100 Gigabit coherent optical transmission module as well as the company's status following Oclaro's merger with Opnext (see below).
The 8-port flexible grid optical channel monitor (OCM) is to address emerging, more demanding requirements of optical networks. "Networks are getting more complex and you need automation so that they are more foolproof and more efficient operationally," says Per Hansen, vice president of product marketing, optical networks solutions at Oclaro.
The 8-port device can monitor up to eight fibres, for example the input and seven output ports of a wavelength-selective switch or an amplifier's outputs.
The programmable OCM can do more than simply go from fibre to fibre, measuring the spectrum. The OCM can dwell on particular ports, or monitor a wavelength on particular ports when the system is adjusting or turning up a wavelength, for example.
"There is processing power included such that you can do a lot of data processing which can then be exported to the line card in the format required," says Hansen. This is important as operators start to adopt flexible-grid network architectures. "[With flexible-grid spectrum] you don't know where channels stop and start such that an OCM that looks at fixed slots in no longer enough," says Hansen.
The OCM can monitor bands finer than 6.25GHz through to the spectrum across the complete C-band.
Oclaro also detailed that its OMT-100 coherent 100 Gigabit optical module is entering volume production. "We have shipped well over 100 [units] to various customers," says Hansen. "There are a lot of system houses looking at this type of module this year." The OMT-100 was developed by Opnext and replaces Oclaro's own MI 8000XM 100 Gigabit module
The company also announced its first 100 Gigabit CFP2 module and its second-generation CFP module 16W power consumption that support the IEEE 100GBASE-LR4 10km standard.
A new small form factor multi-source agreement (MSA) for pump laser diodes was also announced at the show, involving Oclaro and 3S Photonics.
The 10-pin butterfly package is designed to replace the existing 14-pin design. "It is 75% smaller in volume - about two-thirds in each dimension," says Robert Blum, director of product marketing for Oclaro's photonic components. The MSA supports a single cooled or uncooled pump laser, and its smaller volume enables more integrated amplifier designs.
Oclaro says other companies have expressed interest in the MSA and it expects additional players to join.
The New Oclaro
Source: Ovum
Oclaro also gave an update of the company's status following the merger with Opnext earlier this year. The now 3,000-strong company has estimated annual revenues of US $800m. This places the optical component company second only to Finisar.
The merger has broadened the company's product line, adding Opnext's strength in datacom pluggable transceivers to Oclaro's core networking products. The company is also more vertically integrated, using its optical components such as tunable laser and VCSEL technologies, modulators and receivers within its line-side transponders and pluggable optical transceivers.
"You can drive technologies in different directions and not just be out there buying components and throwing them together," says Hansen.
The company also has a range of laser diodes for industrial and consumer applications. "We [Oclaro] were already the largest merchant supplier of high-power laser diodes but now we have a complete portfolio that covers all the wavelengths from 400 up to 1500nm," says Blum.
The company has a broad range of technologies that include indium phosphide, gallium arsenide, lithium niobate, MEMS, liquid crystal and gallium nitride.
An extra business unit has also been created. To the existing optical networks solutions and the photonic components businesses there is now the modules and devices unit covering pluggable and high-speed client side transceivers, and which is based in Japan.
Oclaro-Opnext merger will create second largest optical component company
Oclaro has announced its plan to merge with Opnext. The deal, valued at US $177M, will result in Opnext's shareholders owning 42% of the combined company. The merger of the fifth and sixth largest optical component players, according to Ovum, will create a company with annual revenues of $800M, second only to Finisar. The deal is expected to be completed in the next 3-6 months.
Source: Gazettabyte
Other details of the merger include:
- Combining the two companies will save between $35M-45M but will take 18 months to achieve.
- Restructuring and system integration will cost $20M-$30M.
- All five of the new company's fabs will be kept. The fabs are viewed as key assets.
- The new company will continue its use of contract manufacturers in Asia. Oclaro announced a recent deal with Venture, and that included the possibility of an Oclaro-Opnext merger.
- Oclaro's CEO, Alain Couder, will become the CEO of the new company. Harry Bosco, Opnext's CEO, will join the company's board of directors, made up of six Oclaro and four Opnext members.
- In 4Q 2011, Oclaro reported three customers, each accounting for greater than 10% sales: Fujitsu, Infinera and Ciena. Opnext reported 43% of its sales to Cisco Systems and Hitachi in the same period.
Industry scale
The motivation for the merger is to achieve industry scale, says Oclaro. "We have never been shy [of mergers and acquisitions] - we did Avanex and Bookham," says Yves LeMaitre, chief marketing officer for Oclaro. "We believe industry scale allows you to absorb certain fixed costs like fab infrastructure and the sales force." Scale also increases the absolute amount that can be invested in R&D, estimated at 12-13% of its revenues.
"It [the acquisition] is really about building a company that directly competes with Finisar," says Daryl Inniss, practice leader, components at Ovum. "It creates a stronger, vertically integrated company that starts at chips and goes all the way to the line card."
"We will be one of the most vertically integrated suppliers for 100 Gigabit coherent technology"
Mike Chan, Opnext
LightCounting believes the Oclaro-Opnext merger will be a success. Moreover, the market research firm expects further optical component M&As. Since the Oclaro-Opnext was announced, Sumitomo Electric Device Innovations has announced it will acquire Emcore's VCSEL and associated transceiver technology for $17M.
Meanwhile, Morgan Stanley Research is less positive about the merger, believing that the Opnext acquisition carries 'material risk'. It argues that the stated synergies are aggressive and that the integration of the two firms could distract Oclaro and lower its share price.
Products and technology
The deal expands Oclaro's transceiver portfolio, enhancing its offerings in telecom and strengthening its presence in datacom. It also expands the customer base: Opnext supplies Juniper, Google and H-P, new customers for Oclaro.
Common products shared by the two firms are limited, for high-end products the overlap is mainly 100 Gigabit coherent and tunable laser XFPs. LightCounting also points out that the two share some legacy SONET/SDH, WDM and Ethernet products: "Nothing that reduces competition significantly," it says in a research note.
"[With the Avanex-Bookham merger] There was a little bit of overlap in a few areas which we managed," says Oclaro's LeMaitre. "It is even easier in this case."
"We see potential, further down the road, for new very-short-reach optical interfaces"
Yves LeMaitre, Oclaro
Opnext acquired optical transmission subsystem vendor StrataLight in 2009 while Oclaro acquired Mintera in 2010. Both Oclaro and Opnext have used the expertise of the two subsystem vendors to become early market entrants of 100 Gigabit 168-pin multi-source modules.
But Oclaro makes the optical components for the modules - tunable lasers, lithium niobate modulators and integrated coherent transceivers - items that Opnext has to buy for its 100 Gig coherent module, says Ovum's Inniss: "Opnext has built decent gross margins when you consider that a lot of the optics they don't own themselves.” Oclaro's components will be used within Opnext's modules.
"We will be one of the most vertically integrated suppliers for key 100 Gigabit coherent technology moving forward," says Mike Chan, executive vice president of business development and marketing at Opnext.
Opnext stresses that it has its own programmes for integrated photonics. "We have been telling our customers that we have been working on some of these integrated photonics [for 100G coherent]," says Chan. "The StrataLight portion of Opnext also has a lot of work done, and IP created, in the coherent modem area."
Currently both companies' 100 Gigabit modules use NEL's coherent receiver DSP-ASIC. Oclaro has also made an investment in coherent chip start-up, ClariPhy. But for future coherent adaptive-rate designs, the joint company will be able to develop its own coherent chip. "We have the in-house know-how for the coherent modem chip," says Chan.
The merged company is well positioned to address client-side 100 Gigabit-ber-second (Gbps) transceivers. "Here the challenge is to achieve high density and low power [interfaces]," says Chan. Oclaro has VCSEL technology that can be used for very short reach 4x28Gbps arrays. Oclaro says it is the world's leading supplier of VCSELs for a variety of commercial applications and has now shipped over 150M units.
At OFC/NFOEC Opnext demonstrated a 1310nm LISEL (Lens-integrated Surface-Emitting distributed feedback Laser) array operating at 25-40Gbps. The surface-emitting distributed feedback (DFB) laser can also be used for the same 4x28Gbps design, says Chan. "Within the data centre 500m is the sweet-spot," says Chan. "It is not just the physical distance but the link-budget as the signal may have to go through a patch panel." The DFB can be used with multi-mode and single-mode fibre and Opnext believes it can achieve a 1km reach.
Oclaro does not rule out using its VCSEL technology to address such applications as optical engines, connecting racks and for backplanes. "We see potential, further down the road, for new very-short-reach optical interfaces into consumer, backplane, and board-to-board to really expand our addressable market," says LeMaitre
Further mergers
LightCounting argues that the 2011 floods in Thailand have added urgency to industry consolidation, with the Oclaro and Opnext merger being the first of several. Oclaro and Opnext were among the most impacted by the flood with Q4 2011 revenues being down 18% and 38%, respectively, says LightCounting.
Ovum also expects further mergers as companies strengthen their coherent and ROADM technologies.
Inniss believes ROADMs is the next area that Oclaro is likely to strengthen. Oclaro has acquired Xtellus but Ovum says the main ROADM leaders are Finisar, JDS Uniphase and CoAdna. Companies to watch include JDS Uniphase, Fujitsu Optical Components, CoAdna and Sumitomo, says Inniss.
A day after Ovum's and LightCounting's M&A comments, Sumitomo announced the acquisition of Emcore's VCSEL business unit.
2012: The year of 100 Gigabit transponders
“The world is moving to coherent, there is no question about that”
Per Hansen, Oclaro
The 100Gbps module expands the company's coherent offerings. Oclaro is already shipping a 40Gbps coherent module. “The world is moving to coherent, there is no question about that,” says Per Hansen, vice president of product marketing, optical networks solutions at Oclaro.
Why is this significant?
Having a selection of 100Gbps long-haul optical modules will aid the uptake of high-capacity links in the network core. Opnext announced in September its OTM-100 100Gbps coherent optical module, in production from April 2012. And at least one other module maker has worked with ADVA Optical Networking to make its 100Gbps module, a non-coherent design.
The 100Gbps coherent optical modules will enable system vendors without their own technology to enter the marketplace. It also presents those system vendors with their own 100Gbps technology - the likes of Alcatel-Lucent, Ciena, Cisco and Huawei - with a dilemma: do they continue to evolve their products or embrace optical modules?
“These system vendors have developed [100Gbps] in-house to have a strategic differentiator," says Hansen. "But with lower volumes you have a higher cost.” The advent of 100Gbps modules diminishes the strategic advantage of in-house technology while enabling system vendors to benefit from cheaper, more broadly available modules, he says.
What has been done
Oclaro is still developing the MI 8000XM module and has yet to reveal the reach performance of the module: “We want to do many more tests before we share,” says Hansen. The module will meet the Optical Internetworking Forum's (OIF) 100Gbps module maximum power consumption limit of 80W, he says.
The OIF 100 Gigabit module architecture
The NEL DSP chip is the same device that Opnext is using for its 100Gbps module. “A partnership agreement and sourcing arrangement with NEL allows us to come to market with what we think is a very good product at the right time,” says Hansen.
The DSP uses soft-decision forward error correction. Opnext has said this adds 2-3dB to the optical performance to achieve a reach of 1500-1600km before regeneration.
In 2010 Oclaro announced it had invested US $7.5 million in Clariphy Communications as part of the chip company's development of its 100Gbps coherent receiver chip, the CL10010. As part of the agreement, Oclaro will get a degree of exclusivity as a module supplier (at least one other module maker will also benefit).
ClariPhy has said that while it will not be first to market with a 100Gbps ASIC, the CL10010 will be a 28nm CMOS second-generation chip design. To be able to enter the market with a 100Gbps module next year, Oclaro adopted NEL's design which exists now.
Next
Hansen says that the MI 8000XM, which uses a lithium niobate modulator, is designed to achieve maximum reach and optical performance. But future 100Gbps modules will be developed that may use other modulator technologies and be optimised in terms of power or size.
Hansen is also in no doubt that the next speed hike after 100Gbps will be 400Gbps. Like 100Gbps, there will be some early-adopter operators that embrace the technology one or two years before the consensus.
Such a development is still several years away, however, since an industry standard for 400Gbps must be developed which is only expected in 2014 only.
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.
MultiPhy eyes 40 and 100 Gigabit direct-detect and coherent schemes
MultiPhy's Avi Shabtai (left) and Ronen Weinberg
MultiPhy is developing transceiver designs to boost the transmission performance of metro and long-haul 40 and 100 Gigabit-per-second (Gbps) links. The start-up is aiming its advanced digital signal processing (DSP) chips at direct detection and coherent-based modulation schemes.
“We are the only company, as far as we know, who is doing DSP-based semiconductors for the 40G and 100G direct-detect world,” says Avi Shabtai, CEO of Multiphy.
At 40Gbps the main direct-detection schemes are differential phase-shift keying (DPSK) and differential quadrature phase-shift keying (DQPSK), while at 100Gbps several direct-detect modulation schemes are being considered. “The fact that we are doing DSP at 40G and 100G enables us to achieve much better performance than regular hard-detection technology,” says Shabtai.
Established in 2007, the fabless semiconductor start-up raised US$7.2m in its latest funding round in May. MultiPhy is targeting its physical layer chips at module makers and system vendors. “While there is a clear ecosystem involving optical module companies and systems vendors, there is a lot of overlap,” says Shabtai. “You can find module companies that develop components; you can find system companies that skip the module companies, buying components to make their own line cards.”
MultiPhy’s CMOS chips include high-speed analogue-to-digital converters (ADC) and hardware to implement the maximum-likelihood sequence estimation (MLSE) algorithm. The company is operating the MLSE algorithm at “tens of gigasymbols-per-second”, says Shabtai. “We believe we are the only company implementing MLSE at these speeds.”
MultiPhy's office is alongside Finisar's Israeli headquartersMultiPhy will not disclose the exact sampling rate but says it is sampling at the symbol rate rather than at the Nyquist sampling theorem rate of double the symbol rate. Since commercial ADCs for 100Gbps have been announced that sample at 65Gsample/s, it suggests MultiPhy is sampling at up to half that rate.
MLSE is used to compensate for the non-linear impairments of fibre transmission, to improve overall transmission performance. “We implement an anti-aliasing filter at the input to the ADC and we use the MLSE engine to compensate for impairments due to the low-bandwidth sampling,” says Shabtai.
“There is a good chance that 100Gbps will leapfrog 40Gbps coherent deployments”
Avi Shabtai, MultiPhy
MultiPhy benefits from using one-sample-per-symbol in terms of simplifying the chip design and its power consumption but the MLSE algorithm must counter the resulting distortion. Shabtai claims the result is a significant reduction in power consumption compared to the tradition two-samples-per-symbol approach: “Tens of percent – I won’t say the exact number but it is not 10 percent.”
Other chip companies implementing MLSE designs for optical transmission include CoreOptics, which was acquired by Cisco in May, and Clariphy. (See Oclaro and Clariphy)
Does using MLSE make sense for 40Gbps DPSK and DQPSK?
“If you use DSP for DQPSK at 40Gbps you can significantly improve polarisation mode dispersion tolerance, the limiting factor today of DQPSK transceivers,” says Shabtai. MultiPhy expects the 40 Gigabit direct-detect market to shift towards DQPSK, accounting for the bulk of deployments in two years’ time.
Market applications
MultiPhy is delivering two solutions: for 40 and 100Gbps direct-detect, and 40 and 100Gbps coherent designs. The company has not said when it will deliver products but hinted that first it will address the direct-detect market and that chip samples will be available in 2011.
Not only will the samples enhance the reach of DQPSK-modulation based links but also allow the optical component specifications to be relaxed. For example, cheaper 10Gbps optical components can be used which, says MultiPhy, will reduce total design cost by “tens of percent”.
This is noteworthy, says Shabtai, as the direct-detect markets are increasingly cost-sensitive. “Coherent is being positioned as the high-end solution, and there will be pressure on the direct-detect market to show lower cost solutions,” he says.
MultiPhy is eyeing two 100Gbps spaces
MultiPhy’s view is that direct-detect modulation schemes will be deployed for quite some time due to their price and power advantage compared to coherent detection.
Another factor against 40Gbps coherent technology will be the price difference between 40Gbps and 100Gbps coherent schemes. “There is a good chance that 100Gbps will leapfrog 40Gbps coherent deployments,” he says. “The 40Gbps coherent modules will need to go a long way to get to the right price.” MultiPhy says it is hearing about the expense of coherent modules from system vendors and module makers, as well as industry analysts.
Metro and long-haul
The company says it has received several requests for 40Gbps and 100Gbps direct-detect schemes for the metro due to its sensitivity to cost and power consumption. “We are getting to the point in optical communications where one solution does not fit all – that the same solution for long-haul will also suit metro,” says Shabtai.
He believes 100Gbps coherent will become a mainstream solution but will take time for the technology to mature and its costs to come down. It will thus take time before 100Gbps coherent expands beyond long-haul and into the metro. He also expects a different 100Gbps coherent solution to be used in the metro. “The requirements are different – in reach, in power constraints” he says. “The metro will increasingly become a segment, not only for direct-detect but also for coherent.”
Coherent: Already a crowded market
There are at least a dozen companies actively developing silicon for coherent transmission, while half-a-dozen leading system vendors developing designs in-house. In addition, no-one really knows when the 100Gbps market will take off. So how does MultiPhy expect to fare given the fierce competition and uncertain time-to-revenues?
“It is very hard to predict the exact ramp up to high volumes,” says Shabtai. “At the end of the day, 100Gbps will come instead of 10Gbps and when people look back in five and six years’ time, they will say: ‘Gee, who would have expected so much capacity would have been needed?’.”
The big question mark is when will coherent technology ramp and this explains why MultiPhy is also targeting next-generation direct-detect schemes with its technology. “We cannot come to market doing the same thing as everyone else,” says Shabtai. “Having a solution that addresses power consumption based on one-sample-per-symbol gives us a significant edge.”
MultiPhy admits it has received greater market interest following Cisco’s acquisition of CoreOptics. “While Cisco said it would fulfill all previous commitments, still it worried some of CoreOptics’ customers,” says Shabtai. The acquisition also says something else to Shabtai: 100Gbps coherent is a strategic technology.
Did Cisco consider MultiPhy as a potential acquisition target? “First, I can’t comment, and I wasn’t at the company at the time,” says Shabtai.
As for design wins, Shabtai says MultiPhy is in “advanced discussion” with several leading module and system vendor companies concerning its 40Gbps and 100Gbps direct-detect and coherent technologies.
Further reading
See Opnext's multiplexer IC plays its part in 100Gbps trial
Opnext's multiplexer IC plays its part in 100Gbps trial
AT&T’s 100 Gigabit-per-second (Gbps) coherent trial between Louisiana and Florida detailed earlier this week was notable for several reasons. It included a mix of 10, 40 and 100Gbps wavelengths, Cisco Systems' newest IP core router, the CRS-3, and a 100Gbps line-side design from Opnext.
According to Andrew Schmitt, directing analyst of optical at Infonetics Research, what is significant about the 100Gbps AT&T trial is the real-time transmission; unlike previous 100Gbps trials no received data was block-captured and decoded offline.
Such real-time transmission required the use of Opnext’s 100Gbps coherent design comprising its silicon germanium (SiGe) multiplexer chip, announced in January, and an FPGA mock-up of the receiver circuitry.
"Several industry observers claim coherent detection is the most significant development since the advent of dense wavelength division multiplexing"
The multiplexer IC implements polarisation-multiplexing quadrature phase-shift keying (PM-QPSK) modulation (also known as dual-polarisation QPSK or DP-QPSK) at a line rate of up to 128Gbit/s, to accommodate advanced forward error correction (FEC) needed for 100Gbps transmission.
Yet despite the high speed electronics, the IC can be surface-mounted, simplifying packaging and assembly while reducing the cost of the 100Gbps transponder.
Why is the multiplexer IC important?
To enable the transition to 100Gbps optical transmission its economics needs to be improved. 100Gbps line-side MSA modules are needed to complement emerging IEEE 100 Gigabit Ethernet optical transceivers.
The Optical Internetworking Forum (OIF) backed by industry players have alighted on PM-QPSK as the chosen modulation approach for 100Gbps line-side interfaces. Operators such as AT&T and Verizon also back the technology for 100Gbps deployments.
Such industry recognition of coherent detection using PM-QPSK is based on the technological benefits already demonstrated at 40Gbps by Nortel. Indeed several industry observers claim coherent detection is the most significant development since the advent of dense wavelength division multiplexing (DWDM). While Verizon has stated that its next-generation links will be optimised for 100Gbps coherent transmission.
But developing 100Gbps technology is costly, which is why the OIF and operators are keen to focus the industry’s development R&D dollars on a single technological approach to avoid what has happened for 40Gbps transmission where four modulation schemes were developed and are still being deployed.
Opnext is the first company to detail a 100Gbps multiplexer chip. By operating at 128Gbit/s, the device supports the OIF’s 100Gbps ultra long haul DWDM Framework document yet the chip is packaged within a ball grid array to enable the use of surface-mount manufacturing on the printed circuit board. This avoids the expense and design complications associated with using radio frequency connectors.
The IC could also be used for 40Gbps PM-QPSK transponders. “We might have chosen CMOS [for a 40Gbps design] but there is no reason not to run it at a lower speed,” says Matt Traverso, senior manager, technical marketing at Opnext.
Method used
The multiplexer IC is manufactured using a 0.13 micron SiGe process. The in-house design has been developed by the engineering team Opnext acquired with the purchase of StrataLight.
Design work began a year ago. The resulting chip takes 10 channels, each at up to 11.3Gbit/s, and coverts the data to four 32Gbps channels that are then phase encoded. The multiplexer chip outputs are two polarisations, each comprising two 32Gbps I and Q data streams (see diagram). For a complete 100Gbps line-card diagram, showing the multiplexer IC, demultiplexer/ receiver ASIC that make up the line side and the client-side module, click here.
The input channel rate of 11.3Gbps is to support the Optical Transport Network (OTN) ODU-4 format while the 32Gbps per channel ensures that there is sufficient bit headroom for powerful forward error correction. It is the need to support 32Gbps data rates that required Opnext to use SiGe technology. “CMOS is good for 25 to 28Gbps rates; beyond that for good optical transport you need silicon germanium,” says Traverso.
The consensus however is that the industry will consolidate on CMOS for the multiplexer and demultiplexer/ receiver ICs. It could be that when Opnext defined its multiplexer design goals and timeline, CMOS was not an option.
How was the use of surface-mount technology (SMT) made possible? “The physical interface of the IC was designed based upon SMT packaging models to allow for sufficient margin in the jitter budget to achieve good transmission performance,” says Traverso. “The goal is to match the impedance over frequency from the chip contact through the packaging to the printed circuit board.”
Opnext has not said which foundry it is using to make the chip. Hitachi and IBM are obvious candidates but given Opnext’s history, Hitachi is most likely.
What next?
For 100Gbps line side transmission both multiplexing and demultiplexing circuitry are required. Opnext has detailed the multiplexing circuitry only.
At 100Gbps, the receiver circuitry requires the inverse demultiplexer circuitry – decoding the PM-QPSK signal and recovering the original 100Gbps (10x10Gbps) data. But also required are very high-speed analogue-to-digital converters (ADCs) along with a computationally powerful digital signal processor (DSP).
The ADC and DSP are used to recover the signal, compensating for chromatic and polarisation mode dispersions experienced during transmission. Given the channel data rate is 32Gbps, it implies that the ADCs are operating at 64 Gsample/s.
This is why developing such a chip is expensive and so technically challenging. “It requires finances, technical talent, significant optics expertise, integrated circuit knowledge, DSP design and ADC expertise,” says Traverso.
The reputed fee for developing such an ASIC is US $20m. Given there are at least four system vendors, Opnext, and two transponder/ chip players believed to be developing such an ASIC, this is a huge collective investment. But then the ASIC is where system vendors and transponder makers can differentiate their coherent-based products.
The ASIC also highlights the marked difference between Gigabit Ethernet (GbE) and line-side interfaces.
For 40 and 100GbE transceivers, interoperability between vendors’ transceivers is key. Long-haul connections, in contrast, tend to be proprietary. The industry may have alighted on a common modulation approach but paramount is optical performance. The ASIC, and the DSP and FEC algorithms it executes, is how vendor differentiation is achieved.
At OFC/NFOEC 2010 later this month working 100Gbps PM-QPSK modules are not expected. But it is likely that Opnext and others will detail their 100Gbps demultiplexing/ receiver ASICs. Meanwhile, coherent modules at 40Gbps are expected.
References
[1] “Performance of Dual-Polarization QPSK for Optical Transport Systems” by Kim Roberts et al, click here.
Do multi-source agreements benefit the optical industry?
System vendors may adore optical transceivers but there is a concern about how multi-source agreements originate.
Optical transceiver form factors, defined through multi-source agreements (MSAs), benefit equipment vendors by ensuring there are several suppliers to choose from. No longer must a system vendor develop its own or be locked in with a supplier.
“Personally, the MSA is the worst thing that has happened to the optical industry”
Marek Tlaka, Luxtera
Pluggables also decouple optics from the line card. A line card can address several applications simply by replacing the module. In contrast, with fixed optics the investment is tied to the line card. A system can also be upgraded by swapping the module with an enhanced specification version once it is available.
But given the variety of modules that datacom and telecom system vendors must support, there are those that argue the MSA process should be streamlined to benefit the industry.
Traditionally, several transceiver vendors collaborate before announcing an MSA. The CFP MSA announced in March 2009, for example, was defined by Finisar, Opnext and Sumitomo Electric Device Innovations. Since then Avago Technologies has become a member.
“The industry has an interesting model,” says Niall Robinson, vice president of product marketing at Mintera. “A couple of companies can get together, work behind closed doors and announce suddenly an MSA and try to make it defacto in the market.”
Robinson contrasts the MSA process with the Optical Interconnecting Forum’s (OIF) 100Gbps line side work that defined guidelines for integrated transmitter and receiver modules. Here service providers and system vendors also contributed. “It was a much more effective and fair process, allowing for industry collaboration,” says Robinson
Matt Traverso, senior manager, technical marketing at Opnext, and involved in the CFP MSA, also favours an open process. “But the view that the way MSAs are run is not open is a bit of a fallacy,” he says.
“Any MSA that is well run requires iteration with suppliers,” says Traverso. The opposite is also true: poorly run MSAs have short lives, he says. Having too open a forum also runs the risk of creating a one-size-fits-all: “One vendor may want to use the MSA as a copper interface while a carrier will want it for long-haul dense WDM.”
Optical transceiver vendors benefit in another way if they are the ones developing MSAs. “Transceiver vendors will not make life tough for themselves,” says Padraig OMathuna, product marketing director at optical device maker, GigOptix. “If MSAs are defined by system vendors, [transceiver] designs would be a lot more challenging.”
Avago Technologies argues for standards bodies to play a role especially as industry resources become more thinly spread.
“MSAs are not standards; there are items left unwritten and not enough double checking is done,” says Sami Nassar, director of marketing, fiber optic products division at Avago Technologies. There are always holes in the specifications, requiring patches and fixes. “If they [transceivers] were driven by standards bodies that would be better,” says Nassar.
Organisations such as the IEEE don’t address packaging and connectors as part of their standards work. But this may have to change. “The real challenge, as the industry thins out, is ensuring the [MSA] work is thorough,” says Dan Rausch, Avago’s senior technical marketing manager, fiber optic products division. “The challenge for the industry going forward is ensuring good engineering and more robust solutions.”
Marek Tlalka, vice president of marketing at Luxtera, goes further, questioning the very merits of the MSA: “Personally, the MSA is the worst thing that has happened to the optical industry.”
Unlike the semiconductor industry where a framer chip once on a line card delivers revenue for years, a transceiver company may design the best product yet six months later be replaced by a cheaper competitor. “The return on investment is lost; all that work for nothing,” says Tlalka.
“Is it a good development or not? MSAs are out there,” says Vladimir Kozlov, CEO of optical transceiver market research firm, LightCounting. “It helps system vendors, giving them a freedom to buy.”
But MSAs have squeezed transceiver makers, says Kozlov, and he worries that it is hindering innovation as companies cut costs to maximize their return on investment.
“There is continual pressure to reduce the price of optics,” adds Daryl Inniss, Ovum’s practice leader components. If operators are to provide video and high definition TV services and grow revenues then bandwidth needs to become dirt cheap. “Even today optics is not cheap,” says Inniss. Certainly MSAs play an important role in reducing costs.
“The transceiver vendors’ challenge is our benefit,” admits Oren Marmur, vice president, optical networking line of business, network solutions division at system vendor, ECI Telecom. “But we have our own challenges at the system level.”