Increasingly high bandwidth and low latency applications such as video and internet of things (IoT) are putting pressure on today's networks. This is leading to multiple innovations in optical networking, including better speeds, lower latency and of course, the ability to control and programme the network in real time.
The evolution of applications coupled with increases in capacity has forced optics to innovate to meet demand, says Jeff Smith, head of product development, SSE Enterprise Telecoms. "Optics can now provide multiple, switched and on-demand services in a fluid manor that was previously unthinkable," he says.
As part of this evolution, optical networks are getting faster, with Nokia Bell Labs and Deutsche Telekom claiming to have reached speeds of 1 terabit per second in a field test. Meanwhile, AT&T is trialling 400Gb Ethernet using optical gear from Coriant to carry the service on two closely spaced 200G wavelengths across a long-distance span of its global backbone from New York to Washington.
Advances taking place across different parts of the network include innovation around higher data rates, says Lisa Huff, principal analyst at Discerning Analytics. "We are seeing trials of 300Gb and 400Gb and we are now talking about terabytes," she says.
"200 Gbps transmission speeds are very common in 2017 and even 400 Gbps per one wavelength is available from a few vendors," adds Jan Radil a senior researcher working in optical networks.
According to Bill Kautz, director of strategic solutions marketing at Coriant, the market is now evolving towards disaggregation: the separation of functionality, hardware and software in the network. "Software defined networking (SDN) and network functions virtualisation (NFV) are enablers of this," he says.
Kautz points to the fact that optical systems are starting to offer enhanced performance, better reach and higher bandwidth. "Programmable capabilities provide the ability to makes changes in real time when this was not possible in the past," says Kautz.
All this leads to a better understanding of the network itself. Kautz says: "Awareness in the optical network will see us able to assess it in real time and manage it accordingly."
This opens up multiple opportunities, he says: "When you start to look at this, you can ask: Can I now utilise these programmable capabilities for OpEx reduction, and also on the revenue side in the future?"
For optical networks to be feasible in North America, it is important to tie in programmability with awareness, says Kautz. "This is where SDN comes in. We have service providers to deploy our SDN solutions in North America firstly for CapEx reductions. They have a lot of multiple vendor solutions. Using SDN as an overlay to bypass that speeds up the process and makes service activation more efficient. Once you have done that, you can start tying it to apps and revenue generation services."
Taking recent developments into account, it is now becoming easier for optical networks to meet growing demand. Among the enablers, new and more cost-effective equipment is available, says Radil.
In fact, according to Radil, 10 years ago, the price of 10G dense wavelength division multiplexing (DWDM) XENPAK transceivers was around $30,000 from big vendors and $5,000 from the manufacturers. "Now we can buy CFP2 fully tuneable DWDM transceivers supporting 100, 150, or 200Gbps for around $10,000. This is a huge step and improvement."
So, what kind of applications are optical networks enabling? It depends on the area and need of the customer. Jon Bachtold is chief technology officer at the Central Illinois Regional Broadband Network (CIRBN), an organisation aiming to bridge the digital divide in Illinois. It provides services to K-12 school districts, healthcare, public safety, government, not-for-profit, and commercial institutions.
Bachtold is trying to guide his customers towards apps that drive high bandwidth and better quality. "These are things that fibre can provide over the long term," he explains.
But it's an emerging area, so monetising it can be a challenge: It's difficult to make the case for revenue generation without talking about the apps, says Huff. After all she points out: "It's the apps that make the money, that need the infrastructure. It's all tied together now by seeing what end users require and building infrastructure when they need it. This is difficult for the telecoms industry."
So far, partnering has been seen as a solution to build the networks, Huff explains. For example, traditional telecom providers are partnering with cloud companies.
"Companies including Google, Facebook and Amazon are partnering for submarine cables," she says. "They need to partner with traditional telecoms firms who own the networks and they are doing that."
In addition, the industry is pushing new innovations forward. For example, Facebook's Telecom Infra Project focuses on optical networks with partners including operators, infrastructure providers, and system integrators such as Nokia, Intel and HP Enterprise.
It is seeing Facebook currently working on Open Packet DWDM uses, combining packet and DWDM technology for metro and long-haul fibre optic transport networks. Most recently, Facebook has used Open Packet DWDM to develop a new transponder platform called Voyager.
The momentum and investment is behind it, so the area is gaining traction across the industry. But there are still challenges to be faced, such as coverage. Indeed, Smith says that the last mile' remains the "single largest challenge to consume these services".
In addition, optical networks and the innovations around them such as virtualisation require a transformation of telecoms firms' business models and networks themselves. According to Kautz: "You can never underestimate the challenges that carriers have with legacy services transition."
In addition, says Radil, 'pure networking' knowledge is no longer sufficient: "Now it is true to say physics should be part of networking," he points out.
The challenges are not small, but the industry knows the opportunity is too great to be ignored. The speed and programmability of modern optical networks will provide new revenue streams and efficiencies. Yet this will not be possible unless carriers and internet companies work together to put the right business models, partnerships, and strategies in place.