CableLabs Spec Brings Terabit Fibre Optic Speeds to Access Networks

CableLabs, which is best known for creating the DOCSIS standard that underpins modern cable networks (e.g. Virgin Media in the UK), has today released two new specifications that bring “hyper speed” Point-to-Point Coherent Optics technology to the access network and that means more capacity.

On the surface there’s nothing fundamentally new about Coherent Optics technology, which manipulates laser light as it is sent down a fibre optic cable (i.e. amplitude, phase and polarization) in order to enable much higher transmission speeds.

Major long distance international optical links having been doing this for a long time but bringing it into the much more familiar access network is less familiar territory. Outside of lab tests many operators have preferred to upgrade by simply deploying multiple 10Gbps links that share a single fibre, albeit operating at different wavelengths: Dense Wavelength Division Multiplexing (DWDM).

Naturally there are limits to how many different wavelengths of light and fibres you can use before this approach runs out of steam. By comparison Coherent Optics essentially packs more data into that same light so you can get even faster speeds, albeit without needing to upgrade the cable.

Now you can carry 100Gbps (Gigabits per second) per wavelength of light instead of 10Gbps, which when multiplied could easily reach well into Terabits territory. Perfect for supplying the next generation of broadband ISP connectivity or 5G mobile services with capacity.

Phil McKinney, President and CEO of CableLabs, said:

“CableLabs Point-to-Point Coherent Optics takes the existing [fibre] access network to hyper speed, boosting [fibre] capacity to meet the growing demand of broadband customers. Over half a billion people rely on CableLabs technology every day, and this breakthrough not only increases the capacity of the existing [fibre] system by an order of magnitude, it opens up wavelength resources to improve network quality and reliability, enabling advancements in cellular and wireless services.”

CableLabs have developed two new specifications that apply Coherent Optics to the access network, where shorter distances are more common and costs need to be kept down with appropriate optics (long distance optics are too expensive).

The completed specifications can be found here and it’s another step toward a much more distant future where one day even homes may be linked via Terabit fibres, although for now the new specifications don’t go that deep and remote DAA devices (RPD / Remote PHY Devices above) will still need to be connected via more traditional 10Gbps links.

Naturally CableLabs are more interested in supplying capacity to their DOCSIS using networks, while other firms are developing their own approaches for harnessing Coherent Optics in shorter access networks. Meanwhile CableLabs are also busy working to push 200Gbps+ down each wavelength.