NeoPhotonics' PIC transceiver tackles PON business case
Gazettabyte completes its summary of optical announcements at ECOC, held in Amsterdam. In the third and final part, NeoPhotonics’ GPON multiport transceiver is detailed.
Part 3: NeoPhotonics
“Anything that can be done to get high utilisation of your equipment, which represents your up-front investment, helps the business case"
Chris Pfistner, NeoPhotonics
NeoPhotonics has announced a Gigabit passive optical network (GPON) transceiver designed to tackle the high up-front costs operators face when deploying optical access.
The GPON optical line terminal (OLT) transceiver has a split ratio of 1:128 - a passive optical network (PON) supporting 128 end points - yet matches the optical link budget associated with smaller split ratios. The transceiver, housed in an extended SFP module, has four fibre outputs, each supporting a conventional GPON OLT. The transceiver also uses a mode-coupling receiver implemented using optical integration.
According to NeoPhotonics, carriers struggle with the business case for PON given the relatively low take-up rates by subscribers, at least initially. “Anything that can be done to get high utilisation of your equipment, which represents your up-front investment, helps the business case,” says Chris Pfistner, vice president of product marketing at NeoPhotonics. “With a device like this, you can now cover four times the area you would normally cover.”
The GPON OLT transceiver, the first of a family, has been tested by operator BT that has described the technology as promising.
Reach and split ratio
The GPON transceiver supports up to 128 end points yet meets the GPON Class B+ 28dB link budget optical transceiver specification.
The optical link budget can be traded to either maximise the PON’s distance, limited due to the loss per fibre-km, or to support higher split ratios. However, a larger split ratio increases the insertion loss due to the extra optical splitter stages the signal passes through. Each 1:2 splitter introduces a 3.5dB loss, eroding the overall optical link budget and hence the PON’s reach.
GPON was specified with a Class B 20dB and Class C 30dB link budget. However once PON deployments started a 28dB Class B+ was created to match the practical requirements of operators. For Verizon, for example, a reach of 10-11km covers 95% of its single family units, says NeoPhotonics.
Operators wanting to increase the split ratio to 1:64 need an extra 4dB. This has led to the 32dB link budget Class C+. For shorter runs, in such cases as China, the Class C+ is used for a 1:128 split ratio. “They [operators] are willing to give up distance to cover an extra 1-by-2 split,” says Pfistner.
NeoPhotonics supports the 1:128 split ratio without suffering such loss by introducing two techniques: the mode-coupling receiver (MCR) and boosting the OLT transceiver's transmitter power.
A key issue dictating a PON performance is the sensitivity of the OLT's burst mode receiver. The upstream fibres are fed straight onto the NeoPhotonics’ MCR, eliminating the need for a 4x1 combiner (inverse splitter) and a resulting 6dB signal loss.
The GPON OLT transceiver showing the transmit and the mode-coupling receiver. Source: NeoPhotonics
The MCR is not a new concept, says Pfistner, and can be implemented straightforwardly using bulk optics. But such an implementation is relatively large. Instead, NeoPhotonics has implemented the MCR as a photonic integrated circuit (PIC) fitting the design within an extended SFP form factor.
“The PIC draws on our long experience of planar lightwave circuit technology, and [Santur’s] indium phosphide array technology, to do fairly sophisticated devices,” says Pfistner. NeoPhotonics acquired Santur in 2011.
The resulting GPON transceiver module fits within an SFP slot but it is some 1.5-2cm longer than a standard OLT SFP. Most PON line cards support four or eight OLT ports. Pfistner says a 1:4 ratio is the sweet spot for initial rollouts but higher ratios are possible.
On the transmit side, the distributed feedback (DFB) laser also goes through a 1:4 stage which introduces a 6dB loss. The laser transmit power is suitably boosted to counter the 6dB loss.
Operators
BT has trialled the optical performance of a transceiver prototype. “BT confirmed that the four outputs each represents a Class B+ GPON OLT output,” says Pfistner. Some half a dozen operators have expressed an interest in the transceiver, ranging from making a request to working with samples.
China is one market where such a design is less relevant at present. That is because China is encouraging through subsidies the rollout of PON OLTs even if the take-up rate is low. Pfistner, quoting an FTTH Council finding, says that there is a 5% penetration typically per year: “Verizon has been deploying PON for six years and has about a 30% penetration.”
Meanwhile, an operator only beginning PON deployments will first typically go after the neighbourhoods where a high take-up rate is likely and only then will it roll out PON in the remaining areas.
After five years, a 25% uptake is achieved, assuming this 5% uptake a year. At a 4x higher split ratio, that is the same bandwidth per user as a standard OLT in a quarter of the area, says NeoPhotonics.
“One big concern that we hear from operators is: Now I'm sharing the [PON OLT] bandwidth with 4x more users,” says Pfistner. “That is true if you believe you will get to the maximum number of users in a short period, but that is hardly ever the case.”
And although the 1:128 split ratio optical transceiver accounts for a small part of the carrier’s PON costs, the saving the MCR transceiver introduces is at the line card level. "That means at some point you are going to save shelves and racks [of equipment],” says Pfistner.
Roadmap
The next development is to introduce an MCR transceiver that meets the 32dB Class C+ specification. “A lot of carriers are about to make the switch from B+ to C+ in the GPON world,” says Pfistner. There will also be more work to reduce the size of the MCR PIC and hence the size of the overall pluggable form factor.
Beyond that, NeoPhotonics says a greater than 4-port split is possible to change the economics of 10 Gigabit PON, for GPON and Ethernet PON. “There are no deployments right now because the economics are not there,” he adds.
“The standards effort is focussed on the 'Olympic thought': higher bandwidth, faster, further reach, mode-coupling receiver (MCR) whereas the carriers focus is: How do I lower the up-front investment to enter the FTTH market?” says Pfistner.
Further reading:
GPON SFP Transceiver with PIC based Mode-Coupled Receiver, Derek Nesset, David Piehler, Kristan Farrow, Neil Parkin, ECOC Technical Digest 2012 paper.
Lightwave: Mode coupling receiver increases PON split ratios, click here
Ovum: Lowering optical transmission cost at ECOC 2012, click here
Summary Gazettabyte stories from ECOC 2012, click here
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.
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.
JDSU's Brandon Collings on silicon photonics, optical transport & the tunable SFP+
JDSU's CTO for communications and commercial optical products, Brandon Collings, discusses reconfigurable optical add/drop multiplexers (ROADMs), 100 Gigabit, silicon photonics, and the status of JDSU's tunable SFP+.
"We have been continually monitoring to find ways to use the technology [silicon photonics] for telecom but we are not really seeing that happen”
Brandon Collings, JDSU
Brandon Collings highlights two developments that summarise the state of the optical transport industry.
The industry is now aligned on the next-generation ROADM architecture of choice, while experiencing a ’heavy component ramp’ in high-speed optical components to meet demand for 100 Gigabit optical transmission.
The industry has converged on the twin wavelength-selective switch (WSS) route-and-select ROADM architecture for optical transport. "This is in large networks and looking forward, even in smaller sized networks," says Collings.
In a route-and-select architecture, a pair of WSSes reside at each degree of the ROADM. The second WSS is used in place of splitters and improves the overall optical performance by better suppressing possible interference paths.
JDSU showcased its TrueFlex portfolio of components and subsystems for next-generation ROADMs at the recent European Conference on Optical Communications (ECOC) show. The company first discussed the TrueFlex products a year ago. "We are now in the final process of completing those developments," says Collings.
Meanwhile, the 100 Gigabit-per-second (Gbps) component market is progressing well, says Collings. The issues that interest him include next-generation designs such as a pluggable 100Gbps transmission form factor.
Direct detection and coherent
JDSU remains uncertain about the market opportunities for 100Gbps direct-detection solutions for point-to-point and metro applications. "That area remains murky," says Collings. "It is clearly an easy way into 100 Gig - you don't have to have a huge ASIC developed - but its long-term prospects are unclear."
The price point of 100Gbps direct-detection, while attractive, is competing against coherent transmission solutions which Collings describes as volatile. "As coherent becomes comparable [in cost], the situation will change for the 4x25 Gig [direct detection] quite quickly," he says. "Coherent seems to be the long-term, robust cost-effective way to go, capturing most of the market."
At present, coherent solutions are for long-haul that require a large, power-consuming ASIC. Equally the accompanying optical components - the lasers and modulators - are also relatively large. For the coherent metro market, the optics must become cheaper and smaller as must the coherent ASIC.
"If you are looking to put that [coherent ASIC and optics] into a CFP or CFP2, the problem is based on power; cost is important but power is the black-and-white issue," says Collings. Engineers are investigating what features can be removed from the long-haul solution to achieve the target 15-20W power consumption. "That is pretty challenging from an ASIC perspective and leaves little-to-no headroom in a pluggable," says Collings.
The same applies to the optics. "Is there a lesser set of photonics that can sit on a board that is much lower cost and perhaps has some weaker performance versus today's high-performance long-haul?" says Collings. These are the issues designers are grappling with.
Silicon photonics
Another area in flux is the silicon photonics marketplace. "It is a very fluid and active area," says Collings. "We are not highly active in the area but we are very active with outside organisations to keep track of its progress, its capabilities and its overall evolution in terms of what the technology is capable of."
The silicon photonics industry has shifted towards datacom and interconnect technology in the last year, says Collings. The performance levels silicon photonics achieves are better suited to datacom than telecom's more demanding requirements. "We have been continually monitoring to find ways to use the technology for telecom but we are not really seeing that happen,” says Collings.
Tunable SFP+
JDSU demonstrated its tunable laser in an SFP+ pluggable optical module at the ECOC exhibition.
The company was first to market with the tunable XFP, claiming it secured JDSU an almost two-year lead in the marketplace. "We are aiming to repeat that with the SFP+," says Collings.
The SFP+ doubles a line card's interface density compared to the XFP module. The SFP+ supports both 10Gbps client-side and wavelength-division multiplexing (WDM) interfaces. "Most of the cards have transitioned from supporting the XFP to the SFP+," says Collings. This [having a tunable SFP+] completes that portfolio of capability."
JDSU has provided samples of the tunable pluggable to customers. "We are working with a handful of leading customers and they typically have a preference on chirp or no-chirp [lasers], APD [avalanche photo-diode] or no APD, that sort of thing," says Collings.
JDSU has not said when it will start production of the tunable SFP+. "It won't be long," says Collings, who points out that JDSU has been demonstrating the pluggable for over six months.
The company plans a two-stage rollout. JDSU will launch a slightly higher power-dissipating tunable SFP+ "a handful of months" before the standard-complaint device. "The SFP+ standard calls for 1.5W but for some customers that want to hit the market earlier, we can discuss other options," says Collings.
Further reading
Teraxion embraces silicon photonics for its products
Teraxion has become a silicon photonics player with the launch of its compact 40 and 100 Gigabit coherent receivers.
The Canadian optical component company has long been known for its fibre Bragg gratings and tunable dispersion compensation products. But for the last three years it has been developing expertise in silicon photonics and at the recent European Conference on Optical Communications (ECOC) exhibition it announced its first products based on the technology.
"You don't have this [fabless] model for indium phosphide or silica, while an ecosystem is developing around silicon photonics"
Martin Guy, Teraxion
"We are playing mainly in the telecom business, which accounts for 80% of our revenues," says Martin Guy, vice president, product management & technology at Teraxion. "It is clear that our customers are going to more integration and smaller form-factors so we need to follow our customers' requirements."
Teraxion assessed several technologies but chose silicon photonics and the fabless model it supports. "We are using all our optical expertise that we can apply to this material but use a process already developed for the CMOS industry, with the [silicon] wafer made externally," says Guy. "You don't have this [fabless] model for indium phosphide or silica, while an ecosystem is developing around silicon photonics."
The company uses hybrid integration for its coherent receiver products, with silicon implementing the passive optical functions to which the active components are coupled. Teraxion is using externally-supplied photo-detectors which are flip-chipped onto the silicon for its coherent receiver.
"We need to use the best material for the function for this high-end product," says Guy. "Our initial goal is not to have everything integrated in silicon."
Coherent receiver
A coherent receiver comprises two inputs - the received optical signal and the local oscillator - and four balanced receiver outputs. Also included in the design are two polarisation beam splitters and two 90-degree hybrid mixers.
Several companies have launched coherent receiver products. These include CyOpyics, Enablence, NEL, NeoPhotonics, Oclaro and u2t Photonics. Silicon photonics player Kotura has also developed the optical functions for a coherent receiver but has not launched a product.
One benefit of using silicon photonics, says Teraxion, is the compact optical designs it enables.
The Optical Internetworking Forum (OIF) has specified a form factor for the 100 Gigabit-per-second (Gbps) coherent receiver. Teraxion has developed a silicon photonics-based product that matches the OIF's form factor sized 40mmx32mm. This is for technology evaluation purposes rather than a commercial product. "If customers want to evaluate our technology, they need to have a compatible footprint with their design," explains Guy. This is available in prototype form and Teraxion has customers ready to evaluate the product.
Teraxion will come to market with a second 100 Gigabit coherent receiver design that is a third of the size of the OIF's form factor, measuring 23mmx18mm (0.32x the area of the OIF specification). The compact coherent receivers for 40 and 100Gbps will be available in sample form in the first quarter of 2013.
Teraxion's OIF-specification 100 Gig coherent receiver (left) for test purposes and its compact coherent receiver product. Source: Teraxion
"We match the OIF's performance with this design but there are also other key requirements from customers that are not necessarily in the OIF specification," says Guy.
The compact 100Gbps design is of interest to optical module and system vendors but there is no one view in terms of requirements or the desired line-side form-factor that follows the 5x7-inch MSA. Indeed there are some that are interested in developing a 100 Gigabit CFP module for metro applications, says Guy.
Roadmap
Teraxion's roadmap includes further integration of the coherent receiver's design. "We are using hybrid integration but eventually we will look at having the photo-detectors integrated within the material,” says Guy.
The small size of the coherent design means there is scope for additional functionality to be included. Teraxion says that customers are interested in integrating variable optical attenuators (VOAs). The local oscillator is another optical function that can be integrated within the coherent receiver.
In 2005 Teraxion acquired Dicos Technologies, a narrow line-width laser specialist. Teraxion's tunable narrow line-width laser product - a few kiloHertz wide - is available in the lab. "The purpose of this product is not to be deployed on the line card - right now," says Guy. "We believe this type of performance will be required for next-generation 100 Gig, 400 Gig, 1 Terabit coherent communication systems where you will need a very 'clean' local oscillator."
Teraxion is also working on developing a silicon-photonics-based modulator. The company has been exploring integrating Bragg gratings within silicon waveguides for which it has applied for patents. This is several years out, says Guy, but has the potential to enable high-speed modulators suited for short-reach datacom applications.
MultiPhy targets low-power coherent metro chip for 2013
MultiPhy has given first details of its planned 100 Gigabit coherent chip for metro networks. The Israeli fabless start-up expects to have samples of the device in 2013.
"We can tolerate greater [signal] impairments which means the requirements on the components we can use are more relaxed"
Avi Shabtai, CEO of MultiPhy
"Coherent metro is always something we have pushed," says Avi Shabtai, CEO of MultiPhy. Now, the company says it is starting to see a requirement for coherent technology's deployment in the metro. "Everyone expects to see it [coherent metro] in the next 2-3 years," he says. "Not tomorrow; it will take time to develop a solution to hit the target-specific [metro] market."
MultiPhy is at an advanced stage in the design of its coherent metro chip, dubbed the MP2100C. "It is going to be a very low power device," says Shabtai. MultiPhy is not quoting target figures but in an interview with the company's CTO, Dan Sadot, a figure of 15W was mentioned. The goal is to fit the design within a 24W CFP. This is a third of the power consumed by long-haul coherent solutions.
The design is being tackled from scratch. One way the start-up plans to reduce the power consumption is to use a one-sample-per-symbol data rate combined with the maximum-likelihood sequence estimation (MLSE) algorithm.
MultiPhy has developed patents that involve sub-Nyquist sampling. This allows the analogue-to-digital converters and the digital signal processor to operate at half the sampling rate, saving power. To use sub-Nyquist sampling, a low-pass anti-aliasing filter is applied but this harms the received signal. Using the filter, sampling at half the rate can occur and using the MLSE algorithm, the effects of the low-pass filtering can be countered. And because of the low-pass filtering, reduced bandwidth opto-electronics can be used which reduces cost.
This low-power approach is possible because the reach requirements in metro, up to 1,000km, is shorter than long haul/ ultra long haul optical transmission links. The shorter-reach requirements also impact the forward error correction codes, needed which can lessen the processing load, and the components, as mentioned. "We can tolerate greater [signal] impairments which means the requirements on the components we can use are more relaxed," says Shabtai.
The company also revealed that the MP2100C coherent device will integrate the transmitter and receiver on-chip.
MultiPhy says it is working with several system vendor and optical module partners on the IC development. Shabtai expects the first industry products using the chip to appear in 2014 or 2015. The timing will also be dependent on the cost and power consumption reductions of the accompanying optical components.
A 100Gbps direct-detection optical module showing MultiPhy's multiplexer and receiver ICs. The module shown is a WDM design. Source: MultiPhy
100Gbps direct detection multiplexer chip
MultiPhy has also announced a multiplexer IC for 100 Gigabit direct detection. The start-up can now offer customers the MP1101Q, a 40nm CMOS multiplexer complement to its MP1100Q receiver IC that includes a digital signal processor to implements the MLSE algorithm. The MP1100Q was unveiled a year ago.
Testing the direct-detection chipset, MultiPhy says it can compensate +/-1000ps/nm of dispersion to achieve a point-to-point reach of 55km. No other available solution can meet such a reach, claims MultiPhy.
MultiPhy's direct-detection solution also enables 10 Gigabit-per-second (Gbps) opto-electronics components to be used for the transmit and receive paths. At ECOC, MultiPhy announced that it has used Sumitomo Electric's 10Gbps 1550nm externally-modulated lasers (EMLs) to demonstrate a 40km reach.
Using such 10Gbps devices simplifies the design since no 25Gbps components are required. It will also enable more optical module makers to enter the 100 Gigabit marketplace, claims MultiPhy. "It is twice the distance and about half of the cost of any other solution on the market - much below $10,000," says Shabtai.
MultiPhy's HQ in Ness Ziona, Israel
The multiplexer device can also be used for traditional 4x28Gbps WDM solutions to achieve a reach in existing networks of up to 800km.
MultiPhy says that it expects the overall 100 Gigabit direct detection market to number 4 optical module makers and 4-5 system vendors by the end of 2012. At present ADVA Optical Networking is offering a 100Gbps direct-detection CFP-based design. ECI Telecom has detailed a 5x7-inch MSA direct-detection 100 Gigabit module, while Finisar and Oclaro have both announced that they are coming to market with 100Gbps direct-detection modules.
Optical industry restructuring: The analysts' view
The view that the optical industry is due a shake-up has been aired periodically over the last decade. Yet the industry's structure has remained intact. Now, with the depressed state of the telecom industry, the spectre of impending restructuring is again being raised.
In Part 2, Gazettabyte asked several market research analysts - Heavy Reading's Sterling Perrin, Ovum's Daryl Inniss and Dell'Oro's Jimmy Yu - for their views.
Part II: The analysts' view
"It is just a very slow, grinding process of adjustment; I am not sure that the next five years will be any different to what we've seen"
Sterling Perrin, Heavy Reading
Larry Schwerin, CEO of ROADM subsystem player Capella Intelligent Subsystems, believes optical industry restructuring is inevitable. Optical networking analysts largely agree with Schwerin's analysis. Where they differ is that the analysts say change is already evident and that restructuring will be gradual.
"The industry has not been in good shape for many years," says Sterling Perrin, senior analyst at Heavy Reading. "The operators are the ones with the power [in the supply chain] and they seem to be doing decently but it is not a good situation for the systems players and especially for the component vendors."
Daryl Inniss, practice leader for components at Ovum, highlights the changes taking place at the optical component layer. "There is no one dominate [optical component] supplier driving the industry that you would say: This is undeniably the industry leader," says Inniss.
A typical rule of thumb for an industry in that you need the top three [firms] to own between two thirds and 80 percent of the market, says Inniss: "These are real market leaders that drive the industry; everyone else is a specialist with a niche focus."
But the absence of such dominant players should not be equated with a lack of change or that component companies don't recognise the need to adapt.
"Finisar looks more like an industry leader than we have had before, and its behaviour is that of market leader," says Inniss. Finisar is building an integrated company to become a one-stop-shop supplier, he says, as is the newly merged Oclaro-Opnext which is taking similar steps to be a vertically integrated company. Finisar acquired Israeli optical amplifier specialist RED-C Optical Networks in July 2012.
Capella's Schwerin also wonders about the long term prospects of some of the smaller system vendors. Chinese vendors Huawei and ZTE now account for 30 percent of the market, while Alcatel-Lucent is the only other major vendor with double-digit share.
The rest of the market is split among numerous optical vendors. "If you think about that, if you have 5 percent or less [optical networking] market share, that really is not a sustainable business given the [companies'] overhead expenses," says Schwerin.
However Jimmy Yu, vice president of optical transport research at Dell’Oro Group, believes there is a role for generalist and specialist systems suppliers, and that market share is not the only indicator of a company's economic health. “You have a few vendors that are healthy and have a good share of the market,” he says. “That said, when I look at some of these [smaller] vendors, I say they are better off.”
Yu cites the likes of ADVA Optical Networking and Transmode, both small players with less than 3 percent market share but they are some of the most profitable system companies with gross margins typically above 40 percent. “Do I think they are going to be around? Yes. They are both healthy and investing as needed.”
Innovation
Equipment makers are also acquiring specialist component players. Cisco Systems acquired coherent receiver specialist CoreOptics in 2010 and more recently silicon photonics player, Lightwire. Meanwhile Huawei acquired photonic integration specialist, CIP Technologies in January 2012. "This is to acquire strategic technologies, not for revenues but to differentiate and reduce the cost of their products," says Perrin.
"There is a problem with the rate of innovation coming from the component vendors," adds Inniss. This is not a failing of the component vendors as innovation has to come from the system vendors: a device will only be embraced by equipment vendors if it is needed and available in time.
Inniss also highlights the changing nature of the market where optical networking and the carriers are just one part. This includes enterprises, cloud computing and the growing importance of content service providers such as Google, Facebook and Amazon who buy components and gear. "It is a much bigger picture than just looking at optical networking," says Inniss.
"There is no one dominate [optical component] supplier driving the industry that you would say: This is undeniably the industry leader"
Daryl Inniss, Ovum
Huawei is one system vendor targeting these broader markets, from components to switches, from consumer to the data centre core. Huawei has transformed itself from a follower to a leader in certain areas, while fellow Chinese vendor ZTE is also getting stronger and gaining market share.
Moreover, a consequence of these leading system vendors is that it will fuel the emergence of Chinese optical component players. At present the Chinese optical component players are followers but Inniss expects this to change over the next 3-5 years, as it has at the system level.
Perrin also notes Huawei's huge emphasis on the enterprise and IT markets but highlights several challenges.
The content service providers may be a market but it is not as big an opportunity as traditional telecom. "It is also tricky for the systems providers to navigate as you really can't build all your product line to fit Google's specs and still expect to sell to a BT or an AT&T," says Perrin. That said, systems companies have to go after every opportunity they can because telecom has slowed globally so significantly, he says.
Inniss expects the big optical component players to start to distance themselves, although this does not mean their figures will improve significantly.
"This market is what it is - they [component players] will continue to have 35 percent gross margins and that is the ceiling," says Inniss. But if players want to improve their margins, they will have to invest and grow their presence in markets outside of telecom.
"I like the idea of a Cisco or a Huawei acquiring technology to use internally as a way to differentiate and innovate, and we are going to see more of that," says Perrin.
Thus the supply chain is changing, say the analysts, albeit in a gradual way; not the radical change that Capella's Schwerin suggests is coming.
"It is just a very slow, grinding process of adjustment; I am not sure that the next five years will be any different to what we've seen," says Perrin. "I just don't see why there is some catalyst that suggests it is going to be different to the past two years."
This is based on an article that appears in the Optical Connections magazine for ECOC 2012