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.