A Jolt of Light: CableLabs Holds First 200G P2P Coherent Optics Interop

200G P2P Coherent Optics Interop

Matt Schmitt
Principal Architect

Jul 28, 2022

Anyone remember the jingle for Jolt® Cola? All the sugar and twice the caffeine! Perhaps the phrase dates me, but I still hear it in my head—although I now have new words to set to it:

All the distance and twice the capacity!

OK, maybe it doesn’t have quite the same ring to it. But it’s still exciting because that’s what was demonstrated last month in our labs for Point-to-Point Coherent Optics (P2PCO). We confirmed that devices compliant with CableLabs’ P2PCO PHYv2.0 specification can transmit over roughly the same distance as devices compliant with our P2PCO PHYv1.0 spec, and at double the operating capacity: 200 Gbps vs. 100 Gbps per wavelength. Even more importantly, this result was achieved while also demonstrating multi-vendor interoperability, a key component of achieving scale and promoting competition in the marketplace. All together, these developments allow operators to cost-effectively expand the capacity of the fiber that’s already deployed in their access networks.

We validated interoperability and performance at one of CableLabs’ Interop events, as we’ve done in the past for other technologies, including coherent optics. These events provide an opportunity for multiple manufacturers to get together on neutral ground and test how their products work with each other. In fact, we held Interop events for devices compliant with our P2PCO PHYv1.0 specification, which defines operation at 100 Gbps per wavelength, back in December 2018 and June 2019.

So why the long delay between those tests and June’s Interop? While support for 200 Gbps per wavelength does require new digital signal processor (DSP) silicon, we had originally planned to hold our first 200G event in late 2020. And we all know what happened in 2020—and 2021!

Representing the Majority of the Coherent Optics Industry

Fortunately, the manufacturers didn’t waste that additional time. Instead, they used it to further develop their products. As a result, this was possibly one of the most boring Interop events I’ve ever been a part of—because things simply worked! I won’t claim that troubleshooting wasn’t necessary (it virtually always is), but the manufacturers’ ability to quickly get their devices working with each other was truly impressive.

The Interop participants were:

The number of participants might not be high, but what’s important is that the participants include DSP silicon from multiple manufacturers that represent the majority of the coherent optics industry. Demonstrating interoperability among so many different coherent DSPs bodes incredibly well for operators because it allows them to avoid being locked into single-vendor solutions, which promotes scale and competition.

Another Piece of the 10G Puzzle

As operators move toward the deployment of 10G-capable networks, guaranteeing sufficient capacity across the entire network will be critical for ensuring great customer experiences. P2P coherent optics represents a cost-effective means of increasing the capacity of the existing network. This enables the deployment of new, higher-speed connections into customer homes via technologies like DOCSIS 4.0 at lower costs and opens up new service opportunities, such as support for wireless.

When cable operators deploy coherent termination devices (CTDs) in their network, they may choose to initially deploy them using 100G transceivers. Then, when it’s needed, they can simply replace a pair of transceiver modules with this 200G technology to double the capacity of their network links without relocating or adding other equipment. This allows operators to scale their network capacity quickly and easily based on demand, while spending only what’s needed when it’s needed.

We believe that will serve as an incredibly powerful tool in their toolset, putting in place one more piece of the puzzle that will ultimately power a 10G future.