Although 400G coherent pluggable optics claimed a lot of industry attention in 2021, the state-of-the-art in commercially available systems today is 800Gbps coherent optics powered by 7nm 90+ Gbaud digital signal processing (DSP). In contrast to 400G pluggables, current 800G systems are embedded in line cards – although future developments aim for pluggable options.
To understand the future of high speed coherent optics, Heavy Reading launched the Coherent Optics at 400G, 800G and Beyond Market Leadership Study with industry partners Cisco, Infinera and Juniper. Conducted in September, the survey attracted 81 qualified network operator responses worldwide.
This is the second installment of three blogs highlighting the key findings from the coherent optics project. It focuses on the highest performance end of coherent optics at 800G.
With 800G commercially available from two system suppliers as of 4Q21, a growing number of operators are already deploying 800G-capable systems in their networks. In the survey, 12% of CSPs reported they are already deploying 800G or have plans to deploy by year-end. The next two years look promising for coherent 800G adoption, as an additional 41% of CSPs surveyed expect to deploy during that timeframe. Still, one-third of CSPs (33%) anticipate coherent 800G adoption in 2024 or later. Adoption in the early years skews heavily toward the US market, with US respondents accounting for 100% of the 2021 deployment numbers and continuing as the strongest region through 2023.
Metro versus long haul
Although 800G is identified as the "headline" data rate, multiple combinations of data rate, modulation format and reach are achievable. The important point is that each new generation of DSP provides greater reach at any data rate compared to previous generations. Therefore, 800G coherent optics can address not just metro but also long-haul and even subsea segments – while running at sub-600G data rates.
Looking at vendor and service provider announcements, the vast majority of initial applications have been long haul/subsea as internet content providers (ICPs) and communications service providers (CSPs) seek the maximum data rate over many thousands of kilometers. To understand longer-term service provider plans for embedded 800G coherent optics, Heavy Reading asked service providers to estimate what portion of their metro and long-haul/subsea network wavelengths they expect to be deployed with 800G optics over the next five years.
For long-haul/subsea networks, half expect greater than 20% of wavelengths will be deployed with 800G coherent optics. At 44%, slightly fewer expect greater than 20% of 800G coherent wavelengths in their metro networks over the same timeframe. Results indicate an expected strong role for coherent 800G technology in both the metro and long-haul/subsea segments as CSPs choose the right modulation format to match their capacity and reach their needs.
Finally, Heavy Reading examined the role of DWDM vendor incumbency in CSPs' selection process for 800G coherent optics. The data shows that existing relationships and incumbency are less important than best-in-class performance and other factors. Nearly three-quarters of CSPs surveyed (74%) are at least "somewhat likely" to choose a non-incumbent supplier for 800G, with 17% of the survey group "very likely" to choose a new supplier. Just 6% are "not likely at all" to change suppliers.
Past research in optical networks showed that incumbency is typically a lower priority compared to other selection criteria, including performance and costs. Additionally, on the highest performance end of coherent optics, the high complexity and costs of building optics are causing supplier attrition. Only a handful of DWDM vendors will commercialize embedded 800G. Fortunately for CSPs, the network evolution toward open optical networking with separation of optical transponder technology from the optical line system will ease the introduction of 800G coherent optics from any supplier – including non-incumbents.
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This blog is sponsored by Infinera.
— Sterling Perrin, Principal Analyst, Heavy Reading