Infinera’s ICE6 sends 800 gigabits over a 950km link
Infinera has demonstrated the coherent transmission of an 800-gigabit signal across a 950km span of an operational network.
Infinera used its Infinite Capacity Engine 6 (ICE6), comprising an indium-phosphide photonic integrated circuit (PIC) and its FlexCoherent 6 coherent digital signal processor (DSP).
The ICE6 supports 1.6 terabits of traffic: two channels, each supporting up to 800-gigabit of data.
The trial, conducted over an unnamed operator’s network in North America, sent the 800-gigabit signal as an alien wavelength over a third-party line-system carrying live traffic.
“We have proved not only the state of our 800-gigabit with ICE6 but also the distances it can achieve,” says Robert Shore, senior vice president of marketing at Infinera.
800G trials
Several systems vendors have undertaken 800-gigabit optical trials.
Ciena detailed two demonstrations using its WaveLogic 5 Extreme (WL5e). One was an interoperability trial involving Verizon and Juniper Networks while the second connected two data centres belonging to the operator, Southern Cross Cable, to confirm the deployment of the WL5e cards in a live network environment.
Neither Ciena trial was designed to demonstrated WL5e’s limit of optical performance. Accordingly, no distances were quoted although both links were sub-100km, according to Ciena.
Meanwhile, Huawei has trialled its 800-gigabit technology in the networks of operators Turkcell and China Mobile.
The motivation for vendors to increase the speed of line-side optical transceivers is to reduce the cost of data transport. “One laser generating more data,” says Shore. “But it is not just high-speed transmissions, it is high-speed transmissions over distance.”
Infinera’s first 800-gigabit demonstration involved the ICE6 sending the signal over 800km of Corning’s TXF low-loss fibre.
“We did the demo on that fibre and we realised we had a ton of margin left over after completing the 800-gigabit circuit,” says Shore. The company then looked for a suitable network trial using standard optical fibre.
Infinera used a third-party’s optical line system to highlight that the 950km reach wasn’t due to a combination of the ICE6 module and the company’s own line system.
“What we have shown is that you can take any link anywhere, use anyone’s line system, carrying any kind of traffic, drop in the ICE6 and get 800-gigabit connections over 950km,” says Shore.
ICE 6
Infinera attributes the ICE6’s optical performance to its advanced coherent toolkit and the fact that the company has both photonics and coherent DSP technology, enabling their co-design to optimise the system’s performance.
One toolkit technique is Nyquist sub-carriers. Here, data is sent using several Nyquist sub-carriers across the channel instead of modulating the data onto a single carrier. The ICE6 is Infinera’s second-generation design to use sub-carriers, the first being ICE4, that doubles the number from four to eight.
The benefit of using sub-carriers is that high data rates can be achieved while the baud rate used for each one is much lower. And a lower baud rate is more tolerant to non-linear channel impairments during optical transmission.
Sub-carriers also improve spectral efficiency as the channels have sharper edges and can be packed tightly.
Infinera applies probabilistic constellation shaping to each sub-carrier, allowing fine-tuning of the data each carries. As a result, more data can be sent on the inner sub-carriers and less on the outer two outer sub-carrier where signal recovering is harder.
The sweet spot for sub-carriers is a symbol rate of 8-11 gigabaud (GBd). For the Infinera trial, eight sub-carriers were used, each at 12GBd, for an overall symbol rate of 96GBd.
“While it is best to stay as close to 8-11GBd, the coding gain you get as you go from 11GBd to 12GBd per sub-carrier is greater than the increased non-linear penalties,” says Shore.
Another feature of the coherent DSP is its use of soft-decision forward-error correction (SD-FEC) gain sharing. By sharing the FEC codes, processing resources can be shifted to one of the PIC’s two optical channels that needs it the most.
The result is that some of the strength of the stronger signal can be traded to bolster the weaker one, extending its reach or potentially allowing a higher modulation scheme to be used.
Applications
Linking data centres is one application where the ICE6 will be used. Another is sub-sea optical transmission involving spans that can be thousands of kilometres long, requiring lower modulation schemes and lower data rates.
“It’s not just cost-per-bit and power-per-bit, it is also spectral efficiency,” says Shore. “And a higher-performing optical signal can maintain a higher modulation rate over longer distances as well.”
Infinera says that at 600 gigabits-per-second (Gbps), link distances will be “significantly better” than 1,600km. The company is exploring suitable links to quantify ICE6’s reach at 600Gbps.
The ICE6 is packaged in a 5×7-inch optical module. Infinera’s Groove series will first adopt the ICE6 followed by the XTC platforms, part of the DTN-X series. First network deployments will occur in the second half of this year.
Infinera is also selling the ICE6 5×7-inch module to interested parties.
XR Optics
Infinera is not addressing the 400ZR coherent pluggable module market. The 400ZR is the OIF-defined 400-gigabit coherent standard developed to connect equipment in data centres up to 120km apart.
Infinera is, however, eyeing the emerging ZR+ opportunity using XR Optics. ZR+ is not a standard but it extends the features of 400ZR.
XR Optics is the brainchild of Infinera that is based on coherent sub-carriers. All the sub-carriers can be sent to the same destination for point-to-point links, but they can also be sent to different locations to allow for point-to-multipoint communications. Such an arrangement allows for traffic aggregation.
“You can steer all the sub-carriers coming out of an XR transceiver to the same destination to get a 400-gigabit point-to-point link to compete with ZR+,” says Shore. “And because we are using sub-carriers instead of a single carrier, we expect to get significantly better performance.”
Infinera is developing the coherent DSPs for XR Optics and has teamed up with optical module makers, Lumentum and II-VI.
Other unnamed partners have joined Infinera to bring the technology to market. Shore says that the partners include network operators that have contributed to the technology’s development.
Infinera planned to showcase XR Optics at the OFC conference and exhibition held recently in San Diego.
Shore says to expect XR Optics announcements in late summer, from Infinera and perhaps others. These will detail the XR Optics form factors and how they function as well as the products’ schedules.
Global optical networking market set for solid growth
Source: Ovum
The global optical networking market will grow at a year-over-year rate of 5 percent through 2019. So claims market research firm, Ovum, in its optical networking forecast for 2013 to 2019. North America will lead the market growth, with data centre deployments and demand for 100 Gigabit being the main drivers.
The building of data centres drives demand for optical interconnect. "It [data centre operators] is almost a new category of buyer," says Ian Redpath, principal analyst, network infrastructure at Ovum. The segment is growing faster than telco spending on fixed and mobile networks.
"This whole phenomenon of the large data centre operators is more pronounced in North America, and we think that will continue throughout the forecast period," says Redpath.
Demand for 100 Gigabit is coming from several segments: large incumbent operators, cable operators and internet content service providers. "All these entities are buying a technology [100 Gig] that is prime time," says Redpath.
Asia Pacific will be the region with the second largest growth for the forecast period, at 4.4 percent compound annual growth rate (CAGR).
The deployment of optical equipment in China and Japan was down in 2013: China dipped 6 percent while Japan was down a huge 23 percent compared to 2012 market demand.
The underlying trend in China is one of growth, with the optical market valued at US $3 billion. "They just had to have a pause," says Redpath, who points out that the Chinese market has tripled in a relatively short period. "They are now retooling for the next big thing: LTE; it it just a matter of time," he says. The deployment of 100 Gig, by the large three domestic operators, may start by the year end or spill into 2015.
Optics is the foundation of an industry that is growing
Japan's sharp decline in 2013 follows massive growth in 2012, the result of replacing networks lost following the 2011 earthquake and tsunami. "That was a one-time bump followed by a one-time reset, with the market now back to normal," says Redpath.
Meanwhile, the EMEA optical networking market will growth at 4.1 percent. "This is a pretty modest growth rate, with more upside coming in the latter period," says Redpath. "The operators have been neglecting their core for so long, they are going to have to come back and reinvest."
Ovum says the weakness of the European market will run its course during the forecast period and expects Europe's northern countries - the UK and Germany - to lead the recovery, followed by the likes of Spain, Italy and Greece.
The market research firm singles out the UK market as being particularly dynamic, and an economy that will lead Europe out of recession. "It is probably closer to the North America market than any other country in terms of competitors and non-carrier spending," says Redpath. "The UK is also one of the leading data centre markets in the world."
Ovum remains upbeat about the long-term prospects of the global optical networking market. "Optics is the foundation of an industry that is growing," says Redpath.
He also points to recent developments in the net neutrality debate, and cites how over-the-top TV and film player, Netflix, has signed agreements with telecom and cable operators. "If over-the-top players realise that they can't keep free-riding on these networks, and to get performance they give a little money to the telcos, then that is a good thing for the ultimate food chain," says Redpath.
Further reading:
Global market soft in 1Q14; North America bucks trend, click here
Optical networking spending up in all regions except Europe
Source data: Ovum
Ovum forecasts that the global optical networking market will grow to US $17.5 billion by 2018, a compound annual growth rate of 3.1 percent.
Optical networking spending in North America will be up 9.1 percent in 2013 after two flat years. North American tier-1 service providers and cable operators are investing in the core network to support all traffic types, and 100 Gigabit is being deployed in volume.
In contrast, optical networking sales in EMEA will contract by nearly 10 percent in 2013. “Non-spending in Europe is the major factor in the overall EMEA decline,” says Ian Redpath, principal analyst, network infrastructure at Ovum.
The major technology trend for this forecast is the ascendancy of 100 Gig, whose sales exceeded 40 Gig revenues in 2Q13
EMEA optical networking spending has been down in four out of the past five years, and the lack of investment is becoming acute, says Ovum. Given that service providers are stretching their existing networks, spending will have to take place eventually to make up for the prolonged period of inactivity.
This year has seen 100 Gigabit become the wavelength of choice for large WDM systems, with sales surging. Spending on 100 Gigabit has now overtaken spending on 40 Gigabit which declined in the first half of the year.
"The major technology trend for this forecast is the ascendancy of 100 Gig, whose sales exceeded 40 Gig revenues in 2Q13," says Redpath.
Further reading:
Ovum: Optical networks forecast: top line steady, 100G surging, click here
Optical components: The six billion dollar industry
The service provider industry, including wireless and wireline players, is up 6% year-on-year (2Q10 to 1Q11) to reach US $1.82 trillion, according to Ovum. The equipment market, mainly telecom vendors but also the likes of Brocade, has also shown strong growth - up 15% - to reach revenues of over $41.4 billion. But the most striking growth has occurred in the optical components market, up 28%, to achieve revenues of over $6 billion, says the market research firm.
Source: Ovum
“This is the first time optical components has exceeded six billion since 2001,” says Daryl Inniss, practice leader, Ovum Components. Moreover, the optical component industry growth has continued over six consecutive quarters with the growth being more than 25% for the past four quarters. “None of the other [two] segments have performed in this way,” says Inniss.
Ovum cites three factors accounting for the growth. Fibre-to-the-x (FTTx) is experiencing strong growth while revenues have entered the market from datacom players from the start of 2010. “The [optical] component recovery was led by datacom,” says Inniss. “We speculate that some of that money came from the Googles, Facebooks and Yahoos!.” A third factor accounting for growth has been optical equipment vendors ordering more long lead-time items than needed – such as ROADMs – to secure supply.
Source: Ovum
The second chart above shows the different market segments normalised since the start of 1999. Shown are the capex spending for optical networking, optical networking equipment revenues, optical components and FTTx equipment spending.
Optical networking spending is some 3.5x that of the components. FTTx equipment revenues are lower than the optical component industry’s and is therefore multiplied by 2.25, while capex is 9.2x that of optical equipment. The peak revenue in 2001 is the optical component revenues during the optical boom.
Several points can be drawn from the normalised chart:
- The strong recent growth in FTTx is the result of the booming Chinese market.
- From 2003 to 2008, the overall market showed steady growth, as illustrated by the best-fit line.
- From 2003 to 2008, capex and optical networking revenues were in line, while two thirds of the optical component revenues were due to this telecom spending.
- From 2010 onwards, components deviated from these two other segments due to the datacom spending from new players and the strong growth in FTTx.
- Once the market crashed in early 2009, optical components, networking and capex all fell. FTTx recovered after only one quarter and was followed by optical components. Optical networking and capex, meanwhile, have still not fully recovered when compared with the underlying growth line.
Reflecting light to save power
System vendors will be held increasingly responsible for the power consumption of their telecom and datacom platforms. That’s because for each watt the equipment generates, up to six watts is required for cooling. It is a burden that will only get heavier given the relentless growth in network traffic.
"Enterprises are looking for huge capacity at low cost and are increasingly concerned about the overall impact on power consumption"
David Smith, CIP Technologies
No surprise, then, that the European 7th Framework Programme has kicked-off a research project to tackle power consumption. The Colorless and Coolerless Components for Low-Power Optical Networks (C-3PO) project involves six partners that include component specialist CIP Technologies and system vendors ADVA Optical Networking.
CIP is the project’s sole opto-electronics provider while ADVA Optical Networking's role is as system integrator.
“It’s not the power consumption of the optics alone,” says David Smith, CTO of CIP Technologies. “The project is looking at component technology and architectural issues which can reduce overall power consumption.”
The data centre is an obvious culprit, requiring up to 5 megawatts. Power is consumed by IT and networking equipment within the data centre – not a C-3PO project focus – and by optical networking equipment that links the data centre to other sites. “Large enterprises have to transport huge amounts of capacity between data centres, and requirements are growing exponentially,” says Smith. “They [enterprises] are looking for huge capacity at low cost and are increasingly concerned about the overall impact on power consumption.”
One C-3PO goal is to explore how to scale traffic without impacting the data centre’s overall power consumption. Conventional dense wavelength division multiplexing (DWDM) equipment isn’t necessarily the most power-efficient given that DWDM tunable lasers requires their own cooling. “There is the power that goes into cooling the transponder, and to get the heat away you need to multiply again by the power needed for air conditioning,” says Smith.
Another idea gaining attention is operating data centres at higher ambient temperatures to reduce the air conditioning needed. This idea works with chips that have a wide operating temperature but the performance of optics - indium phosphide-based actives - degrade with temperature such that extra cooling is required. As such, power consumption could even be worse, says Smith
A more controversial optical transport idea is changing how line-side transport is done. Adding transceivers directly to IP core routers saves on the overall DWDM equipment deployed. This is not a new idea, says Smith, and an argument against this is it places tunable lasers and their cooling on an IP router which operates at a relatively high ambient temperature. The power reduction sought may not be achieved.
But by adopting a new transceiver design, using coolerless and colourless (reflective) components, operating at a wider temperature range without needing significant cooling is possible. “It is speculative but there is a good commercial argument that this could be effective,” says Smith.
C-3PO will also exploit material systems to extend devices’ temperature range - 75oC to 85oC - to eliminate as much cooling as possible. Such material systems expertise is the result of CIP’s involvement in other collaborative projects.
"If the [WDM-PON] technology is deployed on a broad scale - that is millions of user lines – every single watt counts"
Klaus Grobe, ADVA Optical Networking
Indeed a companion project, to be announced soon, will run alongside C-3PO based on what Smith describes as ‘revolutionary new material systems’. These systems will greatly improve the temperature performance of opto-electronics. “C-3PO is not dependent on this [project] but may benefit from it,” he says.
Colourless and coolerless
CIP’s role in the project will be to integrate modulators and arrays of lasers and detectors to make coolerless and colourless optical transmission technology. CIP has its own hybrid optical integration technology called HyBoard.
“Coolerless is something that will always be aspirational,” says Smith. C-3PO will develop technology to reduce and even eliminate cooling where possible to reduce overall power consumption. “Whether you can get all parts coolerless, that is something to be strived for,” he says.
Colourless implies wavelength independence. For light sources, one way to achieve colourless operation is by using tunable lasers, another is to use reflective optics.
CIP Technologies has been working on reflective optics as part of its work on wavelength division multiplexing, passive optical networks (WDM-PON). Given such reflective optics work for distances up to 100km for optical access, CIP has considered using the technology for metro and enterprise networking applications.
Smith expects the technology to work over 200-300km, at data rates from 10 to 28 Gigabit-per-second (Gbps) per channel. Four 28Gbps channels would enable low-cost 100Gbps DWDM interfaces.
Reflective transmission
CIP’s building-block components used for colourless transmission include a multi-wavelength laser, an arrayed waveguide grating (AWG), reflective modulators and receivers (see diagram).
Reflective DWDM architecture. Source: CIP Technologies
Smith describes the multi-wavelength laser as an integrated component, effectively an array of sources. This is more efficient for longer distances than using a broadband source that is sliced to create particular wavelengths. “Each line is very narrow, pure and controlled,” says Smith.
The laser source is passed through the AWG which feds individual wavelengths to the reflective modulators where they are modulated and passed back through the AWG. The benefit of using a reflective modulator rather than a pass-through one is a simpler system. If the light source is passed through the modulator, a second AWG is needed to combine all the sources, as well as a second fibre. Single-ended fibre is also simpler to package.
For data rates of 1 or 2Gbps, the reflective modulator used can be a reflective semiconductor optical amplifier (RSOA). At speeds of 10Gbps and above, the complementary SOA-REAM (reflective electro-absorption modulator) is used; the REAM offers a broader bandwidth while the SOA offers gain.
The benefit of a reflective scheme is that the laser source, made athermal and coolerless, consumes far less power than tunable lasers. “It has to be at least half the cost and we think that is achievable,” says Smith.
Using the example of the IP router, the colourless SFP transceiver – made up of a modulator and detector - would be placed on each line card. And the multi-wavelength laser source would be fed to each card’s module.
Another part of the project is looking at using arrays of REAMs for WDM-PON. Such an modulator array would be used at the central office optical line terminal (OLT). “Here there are real space and cost savings using arrays of reflective electro-absorption modulators given their low power requirements,” says Smith. “If we can do this with little or no cooling required there will be significant savings compared to a tunable laser solution.”
ADVA Optical Networking points out that with an 80-channel WDM-PON system, there will be a total of 160 wavelengths (see the business case for WDM-PON). “If you consider 80 clients at the OLT being terminated with 80 SFPs, there will be a cost, energy consumption and form-factor overkill,” says Klaus Grobe, senior principal engineer at ADVA Optical Networking. “The only known solution for this is high integration of the transceiver arrays and that is exactly what C-3PO is about.”
The low-power aspect of C-3PO for WDM-PON is also key. “In next-gen access, it is absolutely vital,” says Grobe. “If the technology is deployed on a broad scale - that is millions of user lines – every single watt counts, otherwise you end up with differences in the approaches that go into the megawatts and even gigawatts.”
There is also a benchmarking issue: the WDM-PON OLT will be compared to the XG-PON standard, the next-generation 10Gbps Gigabit passive optical network (GPON) scheme. Since XG-PON will use time-division multiplexing, there will be only one transceiver at the OLT. But this is what a 40- or 80-channel WDM-PON OLT will be compared with.
CIP will also be working closely with 3-CPO partner, IMEC, as part of the design of the low-power ICs to drive the modulators.
Project timescales
The C-3PO project started in June 2010 and will last three years. The total funding of the project is €2.6 million with the European Union contributing €1.99 million.
The project will start by defining system requirements for the WDM-PON and optical transmission designs.
At CIP the project will employ the equivalent of two full-time staff for the project’s duration though Smith estimates that 15 CIP staff will be involved overall.
ADVA Optical Networking plans to use the results of the project – the WDM-PON and possibly the high-speed transmission interfaces - as part of its FSP 3000 WDM platform.
CIP expects that the technology developed as part of 3-CPO will be part of its advanced product offerings.