As 400GbE becomes increasingly prevalent, there is a growing demand for high-capacity, next-generation metro architectures. However, 400GbE is not an isolated technology but part of a larger puzzle. And as 400GbE advances, it is also setting the stage for the fourth generation of 100GbE requirements.

So, is your network ready to take advantage of these innovations? The good news is the puzzle pieces are coming together to drive the introduction of new products that will help you get there and meet your needs for years to come. Like Ciena’s 8140 Coherent Metro Router, the latest addition to Ciena's routing family.

Before diving into the details of the 8140, let’s first take a step back and take a deeper look at how the 100G story unfolded to get us where we are today. Let's start with the evolution of the physical layer.

Physical Layer

Most networks today use 100GbE with QSFP28. It relies on 4 x 25Gb/s electrical lanes and typically 4 wavelengths over single or multimode fiber. You can think of it as a 'four-by-four' electrical-to-optical approach.

About five years ago, MSA and standards bodies rolled up their sleeves and focused on 100G specifications using a single wavelength. The IEEE created the 100GBASE-DR1 standard for 500m links, while the 100G Lambda MSA and IEEE then followed with 100G-FR1 for 2km and 100G-LR1 for 10km. And they didn’t stop there. The 100G Lambda MSA also defined 100G-ER1 for longer reaches in subsequent years.

Chart of specification Distances

But it is not just about the different specifications (DR1, FR1, etc.) and how far we can go, although the above chart is comprehensive.

The real game-changer for the fourth generation of 100G is tied to the adoption of 4-level pulse amplitude modulation, also known as PAM-4 by the standards. PAM-4 doubles the capacity of links with an advanced modulation scheme, which means we can use just one wavelength for 100G signaling in both the electrical and optical domains.

None of this physical layer evolution happened in a vacuum, though. Here's how the industry achieved a similar outcome for the electrical side of the equation.

SFP-DD: Turning the SFP into a 100GbE module

While the MSA or IEEE standards don't specify which form factor to use for 100G designs, the SFP-DD emerged as the candidate for single-wavelength. This is because the SFP-DD, the smallest form factor of the pluggable optical modules, supports 100 gigabits by doubling the SFP's electrical lanes from one to two and doubling their speed.

Quadrupling the bandwidth of conventional SFP modules was made possible due to advances in router silicon, specifically the evolution of router SerDes from 28 Gbps to 56 Gbps. With these advancements, we are all set to move forward.

The 100G trifecta: Faster SerDes, new SFP-DD form factors and physical layer evolution

It's worth noting that without the advancements in router SerDes and the consideration of new form factors like the SFP-DD, along with the evolution of 100G standards to use PAM-4 modulation, compact next-generation 100GbE routers would not be possible. These are a lot of "what ifs," but they illustrate what a difference five years makes.

The SFP-DD fourth generation of 100GbE is not only a great way to simplify designs, as we've been talking about, but it's also closely related to the rise of the latest generation of routers that boast 400GbE ports. This is because 100GbE uses the same technology as 400GbE with 4x100GbE channels, making upgrading networks with greater operational flexibility possible.

Now, let's examine how the 8140 enables the 100G trifecta we just discussed.

The 8140 value wedge

When it comes to the 8140, we considered power efficiency and footprint carefully. That's why the SFP-DD innovation is such great news! The SFP-DD transceivers are smaller and use less power than the QSFP28, resulting in a denser faceplate.

Ciena's 8140 Coherent Metro Router Ciena’s 8140 Coherent Metro Router

The 8140 is a dense 7.2Tbps switching platform in a compact 2RU footprint with 40 x 100G SFP-DD and 8 x 400G QSFP-DD ports. The 8140 with SFP-DD supports 10GbE SFP+ and 25GbE SFP28 providing flexibility in current deployments and for a seamless migration to dense 100GbE requirements. Of course, it also supports Ciena's industry-leading WaveLogic™ 5 Nano (WL5n) 100G-400G coherent pluggables in all eight QSFP-DD ports, supporting 400ZR, 400ZR+ as well as enhanced performance modes for extended reach to address a broader range of application requirements.

And did I mention that it's born secure as well? You can count on MACsec at line rate on all ports, and it's hardware-ready for IPsec.

Overall, we're seeing a lot of interest in the 8140 for restructuring multi-tiered edge-to-metro networks into scalable spine-leaf topologies or modernization leveraging Ciena’s Coherent Routing solution.

While I’ve initially focused on the hardware innovations, the 8140 comes with SAOS 10, Ciena’s next-generation IP Network Operating System (NOS), and cutting-edge multi-layer operations from Ciena's Manage, Control and Plan (MCP) domain controller, as you would expect.

Wondering what's next for 8140?

Ciena’s 8140 comes to OFC 2023

If you are attending OFC 2023, make sure to visit OIF’s multivendor interoperability demonstration (booth #5101), where we will participate in the 400ZR and CMIS (Common Management Interface Specification) demos.

We will also be doing live demos at the Ciena booth, leveraging Ciena’s 8190 and a remote dark-fiber feed 8140, equipped with the latest Ciena’s WL5n Universal QSFP-DD coherent transceiver over Ciena’s Coherent ELS Open Line System (OLS).

Ciena Coherent Metro Routing with 400G ZRplus

Ciena’s Coherent Metro Routing with 400G ZR+

That might sound like technical jargon, but it’s cool stuff. This setup demonstrates a ROADM capable 400ZR+ and an evolutionary path of the 400ZR single-span interconnect. It paves the way for high-performance pluggable coherent optics in routers for more complex metro architectures.

As the OFC’23 conference approaches, we are excited to showcase our latest innovation in high-speed, high-density multi-terabit metro networks. We look forward to discussing the advances you expect from us and that you can rely on. We hope to see you there!