Top 5 optical transport trends to watch out for in 2021

What are the technologies and trends set to define optical networking over the next 12 months? From ultra-high baud rates to quantum-enhanced security, it's time to look forward to the year ahead.
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2020 was so difficult and disruptive that it’s been somehow curative to spend some time over the holidays thinking about the year ahead and what optical networking trends I expect to play a key a role. Here’s a rundown of my predictions for 2021. 

Open line system (OLS) will evolve for maximum profit from network infrastructure

Despite of the problems associated with the pandemic, the optical industry grew during 2020, and this growth is expected to continue during 2021. But big investments are not leading to big profits. This forces network operators and service providers to squeeze the maximum revenue out of their network infrastructure. I expect that next-generation high-resolution flexgrid ROADMs will ramp up in 2021 due to their ability to maximize spectral efficiency and to enable the efficient transport of high baud rates. They will also be essential to facilitate new revenue opportunities such as spectrum services.

Ultra-high baud rates will be used for minimum cost per bit transport

During 2020 we read about the first trials with 800Gbit/s wavelengths, and we saw solutions coming that leverage even higher channel capacity. The benefit of these approaches is not only in the higher capacity achievable per channel, but in the support of higher baud rates. Why? Operators seek to reduce the cost per bit of transport by maximizing the capacity of their network and minimizing the need for regeneration. The use of higher modulation formats increases the capacity per wavelength, but it also increases the sensitivity to noise, and has a negative impact on the channel reach. Conversely, the use of high baud rates, increases wavelength capacity without impacting maximum reach. The higher the baud rate is, the lower the modulation format to achieve a given data rate. However, the spectral bandwidth increases, which makes low baud rates still a more cost-efficient approach for short-reach applications. “One size doesn’t fit all.” For that reason, I expect that the demand will increase for ultra-flexible software-defined terminals supporting multiple types of modulation formats, high baud rates and wavelength speeds. These terminals will enable network operators to maximize capacity/reach for any link and to reduce cost per bit over any type of network infrastructure.

400G coherent DWDM pluggable optics will rapidly take off 

400G-ZR coherent DWDM pluggable optics will become commercially available in 2021 and will accelerate 400Gbit/s implementation in the market throughout 2021. These optics can be plugged into routers and switches and they offer low cost, low power consumption, high faceplate density and operational simplicity. These characteristics make this subset of 400G coherent pluggable optics ideal for data center interconnect (DCI) applications. However, this shouldn’t mean the end of the 400G transponders market. With their added-value features, such as encryption or demarcation as well as their better performance, ultra-flexible coherent transponders remain an essential component for multiple applications.


Demand will increase for ultra-flexible software-defined terminals supporting multiple types of modulation formats, high baud rates and wavelength speeds.


Direct detect will continue to play an important role

Many people believe that coherent technology will just take over everything over time. However, there are still some use cases where direct-detect solutions will continue to be predominant for a while. For example, in fronthaul and access networks. With short distances and wavelength capacities in the range of 10Gbit/s to 25Gbit/s, compact and cost-efficient G.metro-based solutions with direct-detect 10GNRZ and 25NRZ G.metro-enhanced pluggable optics will be a better fit. Also, in applications with longer reach demands that don’t require the extreme capacity and granularity of metro-core networks, direct-detect interfaces will play a key role. One technology that may resonate in this application area is PAM4 modulation in conjunction with low baud rates, because it seems to be quite robust against both chromatic dispersion and noise.

Quantum-enhanced data security will grow in importance

Recently we’ve read about cyberattacks to some Covid -19 research labs. Could you imagine what the consequences could be if the details of the research for a Covid-19 vaccine were to come into the wrong hands? Corporate data, including intellectual property, needs to be secured against cyberattacks. With the significant steps towards digitalization that were taken in all business areas and countries around the world last year, data security is becoming more crucial than ever before. Data in motion is especially vulnerable. To protect it, the demand for Layer 1 data encryption will continue to grow during 2021 due to the advantages that this solution offers such as lower latency, higher performance, protocol agnosticism and lower cost. Furthermore, with the advent of quantum computers, quantum-enhanced key exchange methods such as post-quantum cryptography (PQC) or quantum key distribution (QKD) on top of the Layer 1 encryption will become more popular, especially for banks, pharmaceutical firms and government networks. 

Moving past Covid

So it looks to me that 2021 will be a significant year for optical transport with some major technological leaps. But more than any other prediction, I wish that the long-awaited arrival of vaccines finally frees us from the Covid-19 threat.

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