Optical Connections Magazine Spring 2023



When it comes to building efficient networks inside data centres and better ones for connecting them to other sites, improved optics are key. Antony Savvas looks at some of the latest developments they can potentially deliver.

CAPACITY Koji Okamoto, vice president for fibre and access business at VIAVI, says of capacity, “With data centre networks (inside and in between), there is a constant need to increase capacity and to meet the ever- increasing needs of cloud and ultra-low latency applications. This means more data centres and interconnects, and more distributed data centres will need to be built out and maintained by increasing density, with more fibres in the same space. This is done by introducing either a greater number of fibres and/or fitting more bits in the same fibre (higher speed or more lanes – wdm).” “This leads to the need to improve the efficiency of the process of building/ commissioning and maintaining/ troubleshooting data centre network environments to ensure that operations scale. As a trend this might seem manageable but there is also the challenge of not enough “fibre-knowledgeable resources”, or skills, in the market, adds Okamoto. “There is also the continuous, and sometimes ubiquitous, build-out of the network edge. With edge computing, more remote data centres and outposts, in addition to more dark fibre within collocated and multi-tenant ecosystems (including service providers), will be needed. This will “blur the lines of demarcation”, says Okamoto, leading

to the need for better maintenance and troubleshooting capabilities, to ensure quality and the rapid isolation of issues. EVOLVING ARCHITECTURES “Data centre architectures are evolving to meet demands for platform flexibility, greater bandwidth, better utilisation, higher density and more complex data,” says Manmeet Walia, director of product marketing at the Synopsys Solutions Group, which provides network design solutions. “The future of data centre network design relies on disaggregation and the broad adoption of co-packaged optics, allowing workloads to use only the resources they need. Disaggregation’s popularity has also grown because of its ability to efficiently process massive workloads needed to stream high- definition movies, play interactive online games, and gain insights from big data analytics,” Walia says. “Optical interconnects are ideal for disaggregated data centre applications because, by transmitting signals via light, they support higher bandwidth and speeds as well as lower latency and power.” As data network speeds continue to increase beyond 400Gbps, so too will the demand for faster device interface speeds and greater sensitivity to latency in data transfer, requiring more energy. This is where co-packaged optics

“Demand for data centre network bandwidth from cloud service providers, which comprise about half of the data centre switch market, is estimated to be growing at 50-60% per year. At the same time, power-per-bit is declining only at half that rate (25-30% per year),” said Sameh Boujelben, analyst and vice president for data centre switch research at Dell’Oro Group. “This means that power consumption in cloud service networks is growing at an unhealthy and unsustainable rate, and will limit service providers’ ability to move to higher speed networks.” Boujelben said optics are a big a part of the problem, as they are estimated to comprise of 50% of the power consumption at a system level with 51.2 Tbps chips, and that portion will continue to increase as we move to next generation chips, he says. “But optics are also a big part of the solution,” adds Boujelben. “Data centre architectures are evolving to accommodate AI/ML (artificial intelligence/machine learning) systems in the back end, growing faster than mainstream networking,” says Vipul Bhatt, VP of marketing for datacom vertical at Coherent. “The optical transceiver industry has kept up admirably, delivering continuous reduction in energy- per-bit and cost-per-bit. Pluggable transceivers with 200G optical lanes are in development now, with support for 200G electrical lanes expected to follow soon.”


| ISSUE 32 | Q1 2023


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