Optical Connections Magazine Spring 2023


can come into play, a single-package integration of electrical and photonic dies that makes miniaturisation requirements more feasible. “Hyperscale data centre applications are driving this new wave of co-packaged optics designs, to address ‘power wall’ and faceplate density limitations, by offering a way to keep rack unit power constant while increasing bandwidth capacity,” says Walia. CPO NEED? “On energy, a useful context to keep in mind is that the networking hardware, which includes optical transceivers, now consumes barely 2% of total energy in a data centre,” adds Coherent’s Bhatt. “The remaining 98% of consumption is by servers, GPUs, memory and infrastructure. This suggests that the case for co-packaged optics (CPO) should be re-examined in terms of the real needs of customers.” “All the market-success rules that apply to pluggable transceivers should apply to CPO as well – cost, yields, scalability, diversity of link types, a vibrant supplier ecosystem, and pay-as-you- grow convenience for customers. That’s why we expect pluggable transceivers to continue to thrive in the market for the foreseeable future, although some AI/ ML interconnects may benefit from the smaller footprint of CPO,” Bhatt says. Martin Vallo, senior analyst at the photonics and sensing division at Yole Intelligence, says, “In recent years we have seen high interest in integrated optics, either for pluggable modules or new co-packaged system architectures for Ethernet applications, and a new architecture enabling optical interconnects for intra-rack applications such as AI training, ML and disaggregation.” Disaggregation refers to the disintegration of the traditional server architecture to create modular, pooled resources, such as pooled microprocessors, pooled memory or pooled storage. “The optical interconnect technology both enables and limits this architecture because the links that were

previously contained on the server board must traverse an entire rack, multiple racks, or across data centres,” says Vallo. Disaggregation promises improved efficiency and data capacity for the data centre but is limited by the cost and performance of the links. “Recent progress on co-packaged optics for Ethernet indicates that main CPO proponents will delay their CPO projects due to spending cuts. It is likely their silicon photonics designs will be leveraged in future pluggable optics.” Vallo maintains the current market opportunity for optical engines remains only for AI/ML, and disaggregation. OpenLight is a newly launched, independent silicon photonics company formed by investments from Synopsys and Juniper Networks. The company introduced its open silicon photonics platform with integrated on-chip indium phosphide (InP) lasers last year. Tom Mader, chief operating officer at OpenLight, says, “Until recently, laser integration and the high cost associated with bolting on discrete lasers was a significant roadblock. But with the advent of on-chip optics and metamaterials like indium phosphide, photonic integrated circuits offer data centres the scalability and cost efficiency they need, while addressing energy efficiency and complex design needs.” He says, “Looking at the near future, network design will continue to shift towards more optics, bringing about a ‘Moore’s Law for photonics’. We’ll see this through extremely efficient voltage scaling, switches that will soon surpass 50 Tbps with 200G lanes, smaller form factors, and easier assembly through on- chip lasers at a lower cost.” Tim Vang, vice president of marketing and applications at Semtech’s signal integrity products group, says, “The integration of clock and data recovery (CDR) and laser drivers delivers lower power consumption, reduced size and scalability to 800Gbps, the data equivalent of streaming more than 200,000 movies simultaneously. In 2023,

optical technology will continue to enhance internal data centre operations to minimise power consumption, cost and latency, while improving bandwidth and speeds for optimal performance.” But while this may well happen, VIAVI’s Okamoto says there are two aspects in fibre optics that must be considered when it comes to data centre network ecosystems. These are multi-fibre push-on (MPO) connectors and fibre monitoring/automation. MPO It’s no secret that demand for increased bandwidth is driving the deployment of high fibre count ribbon cables with multifibre push-on (MPO) connectors.

These cables are present to some degree in all high-capacity optical

environments, from hyperscale networks that require connectivity between and inside individual data centres, to edge compute deployments in support of ultra-low latency in virtually every network application, including for 5G. “Testing MPO infrastructure helps reduce overall cost while achieving faster deployment and monetisation of networks comprised of high fibre count MPO cables,” says Okamoto. FIBRE MONITORING/AUTOMATION Installing, managing and tracking thousands of fibre connections and cabling routes inside and in between data centres, commercial buildings, and campus environments is a real challenge, and it’s not getting technically easier. If not done properly it can lead to many problems during operation of the lit network. “Moving forward, greater automation and control is key, it will help network operators streamline provisioning and monitoring of network connectivity, gain an accurate view of what is connected where in the network, reduce downtime by real-time notification of unauthorised changes, and produce up-to-date reports on the state of the infrastructure,” Okamoto says.

Vipul Bhatt VP Marketing, Datacom Vertical, Coherent

Koji Okamoto VP, Fibre & Access Business, VIAVI

Manmeet Walia Director, Product Marketing, Synopsys Solutions Group

Martin Vallo Senior Analyst, Yole Intelligence

Tom Mader COO, OpenLight

Tim Vang VP, Marketing & Applications, Semtech.


| ISSUE 32 | Q1 2023


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