Moving your optical edge to 100G? Here’s how!

Let’s explore a new way to plug coherent technology into existing edge aggregation infrastructure.

Data traffic demand is exploding, and it’s not going to slow down anytime soon. Our reliance on internet connectivity has significantly increased with the pandemic. At the same time, our expectations have also grown. We don’t just expect to get online. We must have high-speed, secure and reliable connectivity. 

This is forcing network operators to evolve their optical edge infrastructure, and especially to increase transport speeds in their last-mile network. In most cases this means an upgrade from 1Gbit/s to 10Gbit/s rates. That is a ten times capacity increase! This in turn requires the adoption of ten times higher speeds in optical edge aggregation devices, such as optical line terminals (OLT), distributed units (DU) in a 5G architecture or routers. 

Millions of aggregation devices at the optical edge must be upgraded to support 100Gbit/s rates, as well as the DWDM links interconnecting those devices with the optical network core. This can be a costly and overwhelming task for operators. The question is: What’s the most efficient and economical way to do it? Hint: it involves an entirely new product!

100G coherent technology for the optical edge

Direct detect technology has been predominant in access networks. It works well and is a cost-efficient solution for data rates from 10Gbit/s to 25Gbit/s. However, things become tricky at around 100Gbit/s, where direct detect solutions start to show limitations. They are very sensitive to transmission impairments such as chromatic dispersion. As a consequence, 100Gbit/s direct detect solutions are extremely limited regarding reach, and cannot meet the distance requirements of most edge aggregation networks. 

Coherent technology is far more robust and tolerant of line impairments. This simplifies deployment and maintenance and makes optical line system requirements much simpler. Despite these benefits, the power consumption and cost levels of coherent detection have prevented its wide deployment at the optical edge. 

Until now …

As you may have seen in the media, ADVA has announced a new application-specific coherent pluggable device, the ADVA Coherent 100ZR. The new ADVA Coherent 100ZR empowers users to introduce 100Gbit/s coherent links in optical edge aggregation networks at lower cost and with higher operational simplicity than other solutions that are currently commercially available. What makes it different? Here are some of the reasons:

Coherent 100ZR in a 5W QSFP28 pluggable device

The current generation of 100Gbit/s pluggable coherent devices is based on DSP technology that was engineered for 400Gbit/s data center interconnect applications. Suppliers have stripped out the things that aren’t really necessary for 100Gbit/s edge aggregation, but those 100Gbit/s pluggable devices still consume significantly more than 10 watts. This power level isn’t suitable for a QSP28 module, which is the predominant form factor for 100Gbit/s applications at the network edge.

The new ADVA Coherent 100ZR features a new and purpose built DSP, co-developed by ADVA and II- VI incorporated. The small size and low power consumption of this new DSP makes it possible to create a 100Gbit/s coherent pluggable transceiver compliant with the stringent QSFP28 power dissipation requirement of 5 watts.

Edge diagram

Furthermore, the ADVA Coherent 100ZR also meets other important optical edge market requirements:

  • Compatible with any open line system
    Openness, disaggregation and standardization are essential for future proof optical network infrastructure. I talked about it in a blog earlier this year. Of course, these requirements also apply to the optical edge. Coherent 100ZR wavelengths can be transported over any open line system. The ADVA Coherent 100ZR features an open and standardized 100GBASE ZR interface that enables the transport of 100Gbit/s Ethernet as well as OTN OTU4 services over DWDM links stretching up to several hundreds of kilometers with optical amplification. The use of a standardized optical interface, together with a standardized wavelength grid and coherent modulation format, enables users to deploy the ADVA Coherent 100ZR in any existing DWDM optical network with an open line system and classical lambda routing. You can expand or upgrade 10Gbit/s links to 100Gbit/s without major changes in your existing optical network infrastructure.
  • Wavelength auto-tuning technology 
    Given the high number of ports to be upgraded and the cost points of the optical edge, you’ll need to consider a solution that offers both cost-efficiency and operational simplicity. The ADVA Coherent 100ZR pluggable device meets all these requirements. It enables users to build flexible and scalable networks that are easy to deploy and maintain. With a standardized QSFP28 form factor, the ADVA Coherent 100ZR can be plugged directly into any device with QSFP28 ports. What’s more, with industry’s first wavelength auto-tuning technology, no manual configuration is needed. 
  • Hardened design for outdoor deployments
    You may need to place headend devices closer to end users – for example, in street cabinets. If so, then you should also consider the use of hardened equipment that doesn’t require heating and cooling systems, which have a significant impact on costly power consumption. They also add footprint and additional points of failure. The ADVA Coherent 100ZR is available in C- and I- Temp variations and meets a broad range of deployment options. With a hardened design, the I- Temp variant supports temperatures and humidity values beyond the standard operating range. This makes it ideal for harsh outdoor conditions. 

Future-proof your optical edge with Coherent 100ZR

The advent of small form-factor 400Gbit/s pluggable coherent devices with standardized optical interfaces, such as OIF’s 400ZR, have bolstered the upgrade of core and DCI optical network infrastructure to 400Gbit/s. But that approach is not optimized for the optical edge sweet spot, especially at 100Gbit/s. That’s where ADVA’s new 100ZR pluggable coherent device comes in. Its QSFP28 form factor, wavelength auto-tuning and a hardened design for outdoor deployments combine to enable a paradigm shift for the optical edge and an easy upgrade path to 100Gbit/s.

Would you like your optical edge network to benefit from it? We’d be glad to help you.

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