OFC 2025: industry reflections

Gazettabyte is asking industry figures for their thoughts after attending the recent 50th-anniversary OFC show in San Francisco. Here are the first contributions from Huawei’s Maxim Kuschnerov, NLM Photonics' Brad Booth, LightCounting’s Vladimir Kozlov, and Jürgen Hatheier, Chief Technology Officer, International, at Ciena.

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Maxim Kuschnerov, Director of R&D, Huawei

The excitement of last year's Nvidia’s Blackwell graphics processing unit (GPU) announcement has worn off, and there was a slight hangover at OFC from the market frenzy then.

The 224 gigabit-per-second (Gbps) opto-electronic signalling is reaching mainstream in the data centre. The last remaining question is how far VCSELs will go—30 m or perhaps even further. The clear focus of classical Ethernet data centre optics for scale-out architectures is on the step to 448Gbps-per-lane signalling, and it was great to see many feasibility demonstrations of optical signalling showing that PAM-4 and PAM-6 modulation schemes will be doable.

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ECOC 2023 industry reflections - Part 2

Gazettabyte is asking industry figures for their thoughts after attending the recent ECOC show in Glasgow. In particular, what developments and trends they noted, what they learned and what, if anything, surprised them. Here are more responses from LightCounting, Hyper Photonix, NewPhotonics, and Broadcom.

Vladimir Kozlov, CEO of LightCounting, a market research company

Demand for optical connectivity in data centres has accelerated innovation in the industry. ECOC 2023 offered numerous start-ups and established vendors another opportunity to disclose their latest achievements.

The improved reliability of quantum dot lasers was a pleasant surprise. Alfalume presented the latest quantum dot comb laser developments, including continuous power up to 250 mW with a power conversion efficiency of a quarter (25%) and efficient operation of up to 100oC. Preliminary test data suggests that quantum dot lasers offer superior reliability compared to their quantum well counterparts. It would be great to have a reliable laser source, finally.

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The various paths to co-packaged optics

Near package optics has emerged as companies have encountered the complexities of co-packaged optics. It should not be viewed as an alternative to co-packaged optics but rather a pragmatic approach for its implementation.

Co-packaged optics will be one of several hot topics at the upcoming OFC show in March.

Placing optics next to silicon is seen as the only way to meet the future input-output (I/O) requirements of ICs such as Ethernet switches and high-end processors.

Brad Booth

For now, pluggable optics do the job of routing traffic between Ethernet switch chips in the data centre. The pluggable modules sit on the switch platform’s front panel at the edge of the printed circuit board (PCB) hosting the switch chip.

But with switch silicon capacity doubling every two years, engineers are being challenged to get data into and out of the chip while ensuring power consumption does not rise.

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COBO adds co-packaged optics to its agenda

The Consortium of On-Board Optics (COBO) is progressing with its work to create specifications for co-packaged optics.

The decision to address co-packaged optics by an organisation established to promote on-board optics reflects the significant industry interest co-packaged optics has gained in the last year.

So says Brad Booth, director, leading edge architecture pathfinding team in Azure hardware systems and infrastructure at Microsoft.

Source: COBO

The COBO work also complements that of the OIF which has set up its own co-packaged optics framework. 

“We have a different collection of members [to the OIF],” says Booth. “Our members are very strong on optical connectivity and materials whereas the OIF is known for its electrical interface work and module activities like 400ZR.”

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Open Eye MSA gets webscale attention

Microsoft has trialled optical modules that use signalling technology developed by the Open Eye Consortium.

The webscale player says optical modules using the Open Eye’s analogue 4-level pulse-amplitude modulation (PAM-4) technology consume less power than modules with a PAM-4 digital signal processor (DSP).

“Open Eye has shown us at least an ability that we can do better on power,” says Brad Booth, director, next cloud system architecture, Azure hardware systems and infrastructure at Microsoft, during an Open Eye webinar.

Brad BoothOptical module power consumption is a key element of the total power budget of data centres that can have as many as 100,000 servers and 50,000 switches.

“You want to avoid running past your limit because then you have to build another data centre,” says Booth.

But challenges remain before Open Eye becomes a mainstream technology, says Dale Murray, principal analyst at market research firm, LightCounting.

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COBO brings operational benefits to the data centre

Brad Booth admits the hyperscalers have a problem.

“Our operational inefficiencies are massive and it is only going to get worse,” says Booth, principal network architect for Microsoft’s Azure Infrastructure and chair of the Consortium for On-Board Optics (COBO).

The COBO-enabled 12.8-terabit demonstrator switch. Source: COBO

The issue, he says, is that when a switch arrives at the data centre, it comes without the optics installed. The operations staff must unpack the optical modules, plug them into the switch and verify that each is working; an exercise that is repeated thousands of times when they commission a new data centre.

“The time it takes for us to get the network up and running impacts how quickly we can monetise the data centre,” says Booth.

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COBO issues industry’s first on-board optics specification

• COBO modules supports 400-gigabit and 800-gigabit data rates   
• Two electrical interfaces have been specified: 8 and 16 lanes of 50-gigabit PAM-4 signals. 
• There are three module classes to support designs ranging from client-slide multi-mode to line-side coherent optics. 
• COBO on-board optics will be able to support 800 gigabits and 1.6 terabits once 100-gigabit PAM-4 electrical signals are specified. 

Source: COBO

Interoperable on-board optics has moved a step closer with the publication of the industry’s first specification by the Consortium for On-Board Optics (COBO).

COBO has specified modules capable of 400-gigabits and 800-gigabits rates. The designs will also support 800-gigabit and 1.6-terabit rates with the advent of 100-gigabit single-lane electrical signals. 

“Four hundred gigabits can be solved using pluggable optics,” says Brad Booth, chair of COBO and principal network architect for Microsoft’s Azure Infrastructure. “But if I have to solve 1.6 terabits in a module, there is nothing out there but COBO, and we are ready.”

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