ECOC reflections: final part
Gazettabyte asked several attendees at the recent ECOC show, held in Cannes, to comment on key developments and trends they noted, as well as the issues they will track in the coming year.
Dr. Ioannis Tomkos, Fellow of OSA & Fellow of IET, Athens Information Technology Center (AIT)
With ECOC 2014 celebrating its 40th anniversary, the technical programme committee did its best to mark the occasion. For example, at the anniversary symposium, notable speakers presented the history of optical communications. Actual breakthroughs discussed during the conference sessions were limited, however.
Ioannis Tomkos
It appears that after 2008 to 2012, a period of significant advancements, the industry is now more mainstream, and significant shifts in technologies are limited. It is clear that the original focus four decades ago on novel photonics technologies is long gone. Instead, there is more and more of a focus on high-speed electronics, signal processing algorithms, and networking. These have little to do with photonics even if they greatly improve the overall efficient operation of optical communication systems and networks.
Coherent detection technology is making its way in metro with commercial offerings becoming available, while in academia it is also discussed as a possible solution for future access network applications where long-reach, very-high power budgets and high-bit rates per customer are required. However, this will only happen if someone can come up with cost-effective implementations.
Advanced modulation formats and the associated digital signal processing are now well established for ultra-high capacity spectral-efficient transmission. The focus in now on forward-error-correction codes and their efficient implementations to deliver the required differentiation and competitive advantage of one offering versus another. This explains why so many of the relevant sessions and talks were so well attended.
There were several dedicated sessions covering flexible/ elastic optical networking. It was also mentioned in the plenary session by operator Orange. It looks like a field that started only fives years ago is maturing and people are now convinced about the significant short-term commercial potential of related solutions. Regarding latest research efforts in this field, people have realised that flexible networking using spectral super-channels will offer the most benefit if it becomes possible to access the contents of the super-channels at intermediate network locations/ nodes. To achieve that, besides traditional traffic grooming approaches such as those based on OTN, there were also several ground-breaking presentations proposing all-optical techniques to add/ drop sub-channels out of the super-channel.
Progress made so far on long-haul high-capacity space-division-multiplexed systems, as reported in a tutorial, invited talks and some contributed presentations, is amazing, yet the potential for wide-scale deployment of such technology was discussed by many as being at least a decade away. Certainly, this research generates a lot of interesting know-how but the impact in the industry might come with a long delay, after flexible networking and terabit transmission becomes mainstream.
Much attention was also given at ECOC to the application of optical communications in data centre networks, from data-centre interconnection to chip-to-chip links. There were many dedicated sessions and all were well attended.
Besides short-term work on high-bit-rate transceivers, there is also much effort towards novel silicon photonic integration approaches for realising optical interconnects, space-division-multiplexing approaches that for sure will first find their way in data centres, and even efforts related with the application of optical switching in data centres.
At the networking sessions, the buzz was around software-defined networking (SDN) and network functions virtualisation (NFV) now at the top of the “hype-cycle”. Both technologies have great potential to disrupt the industry structure, but scientific breakthroughs are obviously limited.
As for my interests going forward, I intend to look for more developments in the field of mobile traffic front-haul/ back-haul for the emerging 5G networks, as well as optical networking solutions for data centres since I feel that both markets present significant growth opportunities for the optical communications/ networking industry and the ECOC scientific community.
Dr. Jörg-Peter Elbers, vice president advanced technology, CTO Office, ADVA Optical Networking
The top topics at ECOC 2014 for me were elastic networks covering flexible grid, super-channels and selectable higher-order modulation; transport SDN; 100-Gigabit-plus data centre interconnects; mobile back- and front-hauling; and next-generation access networks.
For elastic networks, an optical layer with a flexible wavelength grid has become the de-facto standard. Investigations on the transceiver side are not just focussed on increasing the spectral efficiency, but also at increasing the symbol rate as a prospect for lowering the number of carriers for 400-Gigabit-plus super-channels and cost while maintaining the reach.
Jörg-Peter Elbers
As we approach the Shannon limit, spectral efficiency gains are becoming limited. More papers were focussed on multi-core and/or few-mode fibres as a way to increase fibre capacity.
Transport SDN work is focussing on multi-tenancy network operation and multi-layer/ multi-domain network optimisation as the main use cases. Due to a lack of a standard for north-bound interfaces and a commonly agreed information model, many published papers are relying on vendor-specific implementations and proprietary protocol extensions.
Direct detect technologies for 400 Gigabit data centre interconnects are a hot topic in the IEEE and the industry. Consequently, there were a multitude of presentations, discussions and demonstrations on this topic with non-return-to-zero (NRZ), pulse amplitude modulation (PAM) and discrete multi-tone (DMT) being considered as the main modulation options. 100 Gigabit per wavelength is a desirable target for 400 Gig interconnects, to limit the overall number of parallel wavelengths. The obtainable optical performance on long links, specifically between geographically-dispersed data centres, though, may require staying at 50 Gig wavelengths.
In mobile back- and front-hauling, people increasingly recognise the timing challenges associated with LTE-Advanced networks and are looking for WDM-based networks as solutions. In the next-generation access space, components and solutions around NG-PON2 and its evolution gained most interest. Low-cost tunable lasers are a prerequisite and several companies are working on such solutions with some of them presenting results at the conference.
Questions around the use of SDN and NFV in optical networks beyond transport SDN point to the access and aggregation networks as a primary application area. The capability to programme the forwarding behaviour of the networks, and place and chain software network functions where they best fit, is seen as a way of lowering operational costs, increasing network efficiency and providing service agility and elasticity.
What did I learn at the show/ conference? There is a lot of development in optical components, leading to innovation cycles not always compatible with those of routers and switches. In turn, the cost, density and power consumption of short-reach interconnects is continually improving and these performance metrics are all lower than what can be achieved with line interfaces. This raises the question whether separating the photonic layer equipment from the electronic switching and routing equipment is not a better approach than building integrated multi-layer god-boxes.
There were no notable new trends or surprises at ECOC this year. Most of the presented work continued and elaborated on topics already identified.
As for what we will track closely in the coming year, all of the above developments are of interesting. Inter-data centre connectivity, WDM-PON and open programmable optical core networks are three to mention in particular.
For the first ECOC reflections, click here
Cisco Systems' coherent power move
Cisco Systems announced its intent to acquire the optical transmission specialist CoreOptics back in May. CoreOptics has digital signal processing expertise used to enhance high-speed long-haul dense wavelength division multiplexing (DWDM) optical transmission. Cisco’s acquisition values the German company at US $99m.
"Let me be clear, we don’t believe 100Gbps serial will dominate the market for a long time, or 40Gbps for that matter"
Mark Lutkowitz, Telecom Pragmatics
“It has become clear that Cisco, with a few exceptions, has cornered the coherent market for 40 Gig and 100 Gig,” says Mark Lutkowitz, principal at market research firm, Telecom Pragmatics, which has published a report on Cisco's move.
Prior to Cisco’s move, several system vendors were working with CoreOptics for coherent transmission technology at 40 and 100 Gigabit-per-second (Gbps). Nokia Siemens Networks (NSN) was one and had invested in the company, another was Fujitsu Network Communications. Telecom Pragmatics believes other firms were also working with CoreOptics including Xtera and Ericsson (CoreOptics had worked with Marconi before it was acquired by Ericsson).
ACG Research in its May report Cisco/ CoreOptics Acquisition: What Does It Mean for the Packet Optical Transport Space? also claimed that the Cisco acquisition would set back NSN and Ericsson and listed other system vendors such as ADVA Optical Networking and Transmode that may have been considering using CoreOptics’ 100Gbps multi-source agreement (MSA) design.
“The mere fact that you have all these companies working with CoreOptics - and we don’t know all of them – says it all,” says Lutkowitz. “This was the company they were initially going to be depending on and Cisco made a power move that was brilliant.”
With Cisco bringing CoreOptics in-house, these system vendors will need to find a new coherent technology partner. “The next chance would be with a company like Opnext coming out with a sub-system,” says Lutkowitz. “There is no doubt about it – this was a major coup for Cisco.”
For Cisco, the deal is important for its router business more than its optical transmission business. “In terms of transceivers that go into routers and switches it was absolutely essential that Cisco comes up with coherent technology,” says Lutkowitz. Cisco views transport as a low-margin business unlike IP core routers. “This [acquisition] is about protecting Cisco’s bread and butter – the router business,” he says.
The acquisition also has consequences among the router vendors. Alcatel-Lucent has its own 100Gbps coherent technology which it could add to its router platforms. In contrast, the other main router player, Juniper Networks, must develop the technology internally or partner. Telecom Pragmatics claims Juniper has an internal coherent technology development programme.
40 and 100 Gig markets
Cisco kick-started the 40Gbps market when it added the high-speed interface on its IP core router and Lutkowitz expects Cisco to do the same at 100Gbps. “But let me be clear, we don’t believe 100Gbps serial will dominate the market for a long time, or 40Gbps for that matter.”
In Telecom Pragmatics’ view, multiple channels of 10Gbps will be the predominant approach. First, 10Gbps DWDM systems are widely deployed and their cost continues to come down. And while Alcatel-Lucent and Ciena already have 100Gbps systems, they remain expensive given the infancy of the technology.
But with business with large US operators to be won, systems vendors must have a 100Gbps optical transport offering. Verizon has an ultra-long haul request for proposal (RFP), AT&T has named Ciena as its first domain supplier for its optical and transport equipment but a second partner is still to be announced. And according to ACG Research, Google also has DWDM business.
What next?
Besides Alcatel-Lucent, Ciena, Infinera, Huawei, and now Cisco developing coherent technology, several optical module players are also developing 100Gbps line-side optics. These include Opnext, Oclaro and JDS Uniphase. There are also players such as Finisar that has yet to detail their plans. Lutkowitz believes that if Finisar is holding off developing 100Gbps coherent modules, it may prove a wise move given the continuing strength of the 10Gbps DWDM market.
Opnext acquired subsystem vendor StrataLight Communications in January 2009 and one benefit was gaining StrataLight’s systems expertise and its direct access to operators. Oclaro made its own subsystem move in July, acquiring Mintera. Oclaro has also partnered with Clariphy, which is developing coherent receiver ASICs.
But Telecom Pragmatics questions the long-term prospects of high-end line-side module/ subsystem vendors. “This [technology] is the guts of systems and where the money is made,” says Lutkowitz. “Ultimately all the system vendors will look to develop their own subsystems.”
Lutkowitz highlights other challenges facing module firms. Since they are foremost optical component makers it is challenging for them to make significant investment in subsystems. He also questions when the market 100Gbps will take off. “Some of our [market research] competitors talk about 2014 but they don’t know,” says Lutkowitz.
But is not the trend that over time, 40Gbps and 100Gbps modules will gain increasing share of the line side systems optics, as has happened at 10Gbps?
That is certainly LightCounting’s view that sees Cisco’s move as good news for component and transceiver vendors developing 40 and 100Gbps products. LightCounting argues that with Cisco’s commitment to the technology, other system vendors will have to follow suit, boosting demand for the higher-margin products.
“There will be all types of module vendors but it is possible that going higher in the food chain will not work out,” says Lutkowitz. “There will be more module and component vendors than we have now but all I question is: where are the examples of companies that have gone into subsystems that have done relatively well?”
Opnext is likely to be the next vendor with 100Gbps product, says Lutkowitz, and Oclaro could easily come out with its own offering. “All I’m saying is that there is a possibility that, in the final analysis, systems vendors take the technology and do it themselves.”
ECOC 2009: Squeezing optics out of optical communications
Prof. Polina BayvelAn interview with Polina Bayvel, Professor of Optical Communications and Networks and head of the Optical Networks Group at University College London (UCL), on her ECOC conference impressions.
What did you find noteworthy at ECOC 2009?
PB: So much work on digital signal processing and coherent detection...will these techniques lead to another revolution in fibre optics? But there is much to understand about how to design the DSP algorithms and how to best match these to appropriate fibre maps in some implementable way.
Did anything at the conference surprise you?
PB: Is there really a capacity crunch or is it a cost crunch and who will end up paying? There is much work on new fibres, new DSP but why is no-one looking at new amplifiers?
What did you learn from ECOC?
PB: I learnt how little progress there has been made in all-optical networking - the well-trodden ideas and arguments on wavelength routing which have been circulating for over 15 years are not being taken up by operators but are being re-discovered and re-offered as new...and just how conservative the operators still are, except those in Japan.
Did you see or hear anything that gives reason for industry optimism?
PB: Lots of buzz about linear and nonlinear DSP, error correcting codes, net coding gain, FPGAs and many other developments which, whilst invigorating the industry are squeezing optics out of optical communications. Here is to the fightback for optics!