Mellanox to acquire silicon photonics player Kotura
Source: Gazettabyte
Mellanox Technologies has announced its intention to acquire silicon photonics player, Kotura, for $82 million.
The acquisition will enable Mellanox to deliver 100 Gigabit Infiniband and Ethernet interconnect in the coming two years. lt will also provide Kotura with the resources needed to bring its 100 Gigabit QSFP to market. Mellanox will also gain Kotura's optical engine for use in active optical cables and new mid-plane platform designs, as well as future higher speed interfaces.
The news is also significant for the optical component industry. Kotura is one of the three established merchant silicon photonics players - the others being LightWire and Luxtera - that have spent years developing their technologies.
LightWire was acquired by Cisco Systems in March 2012 for US $271 million and now Mellanox plans to acquire Kotura. The two equipment vendors recognise the value of the technology, bringing it in-house to reduce system interconnect costs and as a long term differentiator for their equipment and ASIC designs. Mellanox, as a silicon photonics player, will compete with Intel, with its own silicon photonics technology, and Cisco Systems.
Kotura has been using its technology to sell telecom products such as variable optical attenuators and multiplexers. The start-up recently announced its 100 Gig QSFP that uses wavelength division multiplexing (WDM) transmitter and receiver chips. The product is to become available in 2014.
In an interview last year, Kotura's CTO, Mehdi Asghari, discussed a roadmap showing how its 100 Gigabit silicon photonics technology could scale to 400 Gigabit and eventually 1.6 Terabit.
"Our devices are capable of running at 40 or 50 Gigabit-per-second (Gbps), depending on the electronics. The electronics is going to limit the speed of our devices. We can very easily see going from four channels at 25Gbps to 16 channels at 25Gbps to provide a 400 Gigabit solution," Asghari told Gazettabyte.
Kotura also discussed how the line rate could be increased to 50Gbps either using a non-return-to-zero (NRZ) line rate or using a multi-level modulation such as pulse amplitude modulation (PAM).
"To get to 1.6 Terabit transceivers, we envisage something running at 40Gbps times 40 channels or 50Gbps times 32 channels. We already have done a single receiver chip demonstrator that has 40 channels, each at 40Gbps," said Asghari.
"These things in silicon are not a big deal. The III-V guys really struggle with yield and cost. But you can envisage scaling to that level of complexity in a silicon platform."
Silicon photonics will not replace existing VCSEL or indium phosphide-based transceiver designs. But there is no doubting silicon photonics is emerging as a key optical technology and the segment is heating up.
If the early start-ups are being acquired, there have been more recent silicon photonics players entering the marketplace such as Aurrion, Skorpios Technologies and Teraxion. There are also internal developments among equipment players such as Alcatel-Lucent, HP Labs and IBM. Indeed Kotura has worked closely with Oracle (Sun Microsystems)
Further acquisitions of silicon photonic players should be expected as companies start designing next generation, denser systems and adopt 100 Gigabit and faster interfaces.
Equally, established optical component and module companies will likely enter quietly (and not so quietly) the marketplace adding silicon photonics to their technology toolkits when the timing is right.
Trends to watch
Two industry trends are underway regarding silicon photonics.
The first is system vendors wanting to own the technology to reduce their costs while recognising a need to control and understand the technology as they tackle more complex equipment designs.
The other, what at first glance is a contrarian trend, is the democratisation of silicon photonics.
The technology is slowly passing from the select few to become more generally available for industry use. For this to happen, the relevant design tools need to mature as do third-party fabrication plants that will manufacture the silicon photonics designs.
Appendix:
On June 4th, 2013, Mellanox announced a definitive agreement to acquire chip company IPtronics for $47.5 million as it builds out its in-house technologies for optical interconnect. Click here
Futher reading:
Avago to acquire CyOptics, click here
Kotura demonstrates a 100 Gigabit QSFP
“QSFP will be the long-term winner at 100 Gig; the same way QSFP has been a high volume winner at 40 Gig”
Arlon Martin, Kotura
The device is aimed at plugging the gap between vertical-cavity surface-emitting laser (VCSEL) -based 100GBASE-SR10 designs that have span 100m, and the CFP-based 100GBASE-LR4 that has a 10km reach.
“It is aimed at the intermediate space, which the IEEE is looking at a new standard for," says Arlon Martin, vice president of marketing at Kotura.
The device is similar to Luxtera's 100 Gigabit-per-second (Gbps) QSFP, also detailed at the OFC/NFOEC 2013 exhibition, and is targeting the same switch applications in the data centre. “Where we differ is our ability to do wavelength-division multiplexing (WDM) on a chip,” says Martin. Kotura also uses third-party electronics such as laser drivers and transimpedance amplifiers (TIA) whereas Luxtera develops and integrates its own.
The Kotura QSFP uses four wavelengths, each at 25Gbps, that operate around 1550nm. “We picked 1550nm because that is where a lot of the WDM applications are," says Martin. “There are also some customers that want more than four channels.” The company says it is also doing development work at 1310nm.
Although Kotura's implementation doesn't adhere to an IEEE standard - the standard is still work in progress - Martin points out that the 10x10 MSA is also not an IEEE standard, yet is probably the best selling client-side 100Gbps interface.
Optical component and module vendors including Avago Technologies, Finisar, Oclaro, Oplink, Fujitsu Optical Components and NeoPhotonics all announced CFP2 module products at OFC/NFOEC 2013. The CFP2 is the next pluggable form factor on the CFP MSA roadmap and is approximately half the size of the CFP.
The advent of the CFP2 enables eight 100Gbps pluggable modules on a system's front panel compared to four CFPs. But with the QSFP, up to 24 modules can be fitted while 48 are possible when mounted double sidedly - ’belly-to-belly’ - across the panel. “QSFP will be the long-term winner at 100 Gig; the same way QSFP has been a high volume winner at 40 Gig,” says Martin.
The QSFP uses 28Gbps pins, which is also called the QSFP28, but Kotura refers to it 100Gbps product as a QSFP. The design consumes 3.5W and uses two silicon photonic chips. Kotura says 80 percent of the total power consumption is due to the electronics.
One of the two chips is the silicon transmitter which houses the platform for the four lasers (gain chips) combined as a four-channel array. Each is an external cavity laser where part of the cavity is within the indium phosphide device and the rest in the silicon photonics waveguide. The gain chips are flip-chipped onto the silicon. The transmitter also includes a grating that sets each laser's wavelength, four modulators, and a WDM multiplexer to combine the four wavelengths before transmission on the fibre.
Kotura's 4x25 Gig transmitter and receiver chips. Source: Kotura
The receiver chip uses a four-channel demultiplexer with each channel fed to a germanium photo-detector. Two chips are used as it is easier to package each as a transmitter optical sub-assembly (TOSA) or receiver optical sub-assembly (ROSA), says Martin. The 100Gbps QSFP will be generally available in 2014.
Disruptive system design
The recent Compass-EOS IP router announcement is a welcome development, says Kotura, as it brings the optics inside the system - an example of mid-board optics - as opposed to the front panel. Compass-EOS refers to its novel icPhotonics chip combining a router chip and optics as silicon photonics but in practice it is an integrated optics design. The 168 VCSELs and 168 photodetectors per chip is massively parallel interconnect, says Martin.
“The advantage, from our point of view of silicon photonics, is to do WDM on the same fibre in order to reduce the amount of cabling and interconnect needed,” he says. At 100 Gigabit this reduces the cabling by a factor of four and this will grow with more 25Gbps wavelength channels used to 10x or even 40x eventually.
“What we want to do is transition from the electronics to the optical domain as close to those large switching chips as possible,” says Martin. “Pioneers [like Compass-EOS] demonstrating that style of architecture are to be welcomed."
Kotura says that every company that is building large switching and routing ASICs is looking at various interface options. "We have talked to quite a few of them,” says Martin.
One solution suited to silicon photonics is to place the lasers on the front panel while putting the modulation, detection and WDM devices - packaged using silicon photonics - right next to the ASICs. This way the laser works at the cooler room temperature while the rest of the circuitry can be at the temperature of the chip, says Martin.
Avago's latest optical engine targets active optical cables
Avago Technologies has unveiled its first family of active optical cables for use in the data centre and for high performance computing.
The company has developed an optical engine for use in the active optical cables (AOCs). Known as the Atlas 75x, the optical engine reduces the power consumption and cost of the AOC to better compete with direct-attach copper cables.
“Some 99 percent of [active optical cable] applications are 20m or less”
Sharon Hall, Avago
"This is a price-elastic market," says Sharon Hall, product line manager for embedded optics at Avago Technologies. "A 20 percent price premium over a copper solution, then it starts to get interesting."
The AOC family comprises a 10 Gigabit-per-second (Gbps) single channel SFP+ and two QSFP+ cables - a 4x10Gbps QSFP+ and a QSFP+-to-four SFP+. The SFP+ AOC is used for 10 Gigabit Ethernet, 8 Gigabit Fibre Channel and Infiniband applications. The QSFP+ is used for 4-channel Infiniband, serial-attached SCSI (SAS) storage while the QSFP-to-four-SFP+ is required for server applications.
There are also three 12-channel CXP AOC products: 10-channel and 12-channel cables with each channel at 10Gbps; and a 12-channel CXP, each at 12.5Gbps. The devices supports the 100GBASE-SR10 100 Gigabit Ethernet and 12-channel Infiniband standards.
The 12-channel 12.5Gbps CXP product is used typically for proprietary applications such as chassis-to-chassis links where greater bandwidth is required, says Avago.
The SFP+ and QSFP+ products have a reach of 20m whereas competing AOC products achieve 100m. “Some 99 percent of applications are 20m or less,” says Hall.
The SFP+ and QSFP+ AOC products use the Atlas 75x optical engine. The CXP cable uses Avago’s existing Atlas 77x MicroPod engine and has a reach of 100m.
The Atlas 75x duplex 10Gbps engine reduces the power consumption by adopting a CMOS-based VCSEL driver instead of a silicon germanium one. “With CMOS you do not get the same level of performance as silicon germanium and that impacts the reach,” says Hall. “This is why the MicroPod is more geared for the high-end solutions.”
The result of using the Atlas 75x is an SFP+ AOC with a power consumption of 270mW compared to 200mW of a passive direct-attach copper cable. However, the SFP+ AOC has a lower bit error rate (1x10-15 vs. 1x10-12), a reach of up to 20m compared to the copper cable’s 7m and is only a quarter of the weight.
The SFP+ AOC does have a lower power consumption compared to active direct-attach cable, which consumes 400-800mW and has a reach of 15m.
Avago says that up to a 30m reach is possible using the Atlas 75x optical engine. Meanwhile, samples of the AOCs are available now.
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).
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.
Next-gen 100 Gigabit short reach optics starts to take shape
The latest options for 100 Gigabit-per-second (Gbps) interfaces are beginning to take shape following a meeting of the IEEE 802.3 Next Generation 100Gb/s Optical Ethernet Study Group in November.
The interface options being discussed include:
- A parallel multi-mode fibre using a VCSEL with a reach of 50m to 70m. An active optical cable version with a 30m reach, limited by the desired cable length rather than the technology, using silicon photonics or a VCSEL has also been proposed.
- A parallel single-mode fibre using a 1310nm electro-absorption modulated laser (EML) or silicon photonics with a range of 50m to 1000m+.
- A duplex single-mode fiber, using wavelength division multiplexing (WDM) or pulse-width modulation (PAM), an EML or silicon photonics for a 2km reach.
“I think in the end all will be adopted,” says Marek Tlalka, director of marketing at Luxtera. "Users will be able to choose what is most economical."
Jon Anderson, director of technology programme at Opnext, stresses however that these are proposals.
"No decisions were reached by the Study Group on any of these proposals," he says. “The Study Group is only working towards defining objectives for a next-gen 100 Gigabit Ethernet Optics project.” Agreement on technical solutions is outside the scope of the Study Group.
Anderson says there is a general agreement to define a 4x25Gbps multi-mode fibre optical interface. But the issues of reach and multi-mode fibre type (OM3, OM4) are still being studied.
“The Study Group has not reached any agreement on whether a 100GE short reach single-mode objective should be pursued," says Anderson. “Discussion at this point are on reach, power consumption and relative cost of possible solutions with respect to (the 10km) 100GBASE-LR4."