Enfabrica’s chip tackles AI supercomputing challenges

• Enfabrica’s accelerated compute fabric chip is designed to scale computing clusters comprising CPUs and specialist accelerator chips.
• The chip uses memory disaggregation and high-bandwidth networking for accelerator-based servers tackling artificial intelligence (AI) tasks.

Rochan Sankar

For over a decade, cloud players have packed their data centres with x86-based CPU servers linked using tiers of Ethernet switches.

“The reason why Ethernet networking has been at the core of the infrastructure is that it is incredibly resilient,” says Rochan Sankar, CEO and co-founder of Enfabrica.

But the rise of AI and machine learning is causing the traditional architecture to change.

What is required is a mix of processors: CPUs and accelerators. Accelerators are specialist processors such as graphics processing units (GPUs), programmable logic (FPGAs), and custom ASICs developed by the hyperscalers.

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How DSP smarts continue to improve optical transport

• Kim Roberts explains the signal processing techniques Ciena is using for its WaveLogic 6 coherent DSP.
• Roberts explains how the techniques squeeze, on average, a 15 per cent improvement in spectral efficiency.
• The WaveLogic 6 Extreme chip can execute 1,600 trillion (1.6 x 10¹⁵) operations per second and uses the equivalent of 4km of on-chip copper interconnect.

Part 2: WaveLogic 6's digital signal processing toolkit

Kim Roberts, Ciena’s vice president of WaveLogic Science and winner of the 2019 John Tyndall Award

Bumping into Kim Roberts on the way to the conference centre at OFC, held in San Diego in March, I told him how, on the Ciena briefing about its latest WaveLogic 6 coherent digital signal processor (DSP), there had been insufficient time to dive deeply into the signal processing techniques used.

“What are you doing now?” said Roberts.

“I’m off to the plenary session to catch the keynotes.”

Chatting some more, I realised I was turning down a golden opportunity to sit down with a leading DSP and coherent modem architect.

“Is that offer still open?” I asked.

He nodded.

We grabbed a table at a nearby cafe and started what would prove to be an hour-long conversation.

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Marvell’s CTO: peering into the future is getting harder

CTO interviews part 4: Noam Mizrahi

In a wide-ranging interview, Noam Mizrahi (pictured), executive vice president and corporate chief technology officer (CTO) at Marvell, discusses the many technologies needed to succeed in the data centre. He also discusses a CTO’s role and the importance of his focussed thinking ritual.

Noam Mizrahi has found his calling.

“I’m inspired by technology,” he says. “Every time I see an elegant technical solution - and it can be very simple - it makes me smile.”

Marvell hosts an innovation contest, and at one event, Mizrahi mentioned this to participants. “So they issued stickers saying, ‘I made Noam smile’,” he says.

Marvell’s broad portfolio of products spans high-end processors, automotive Ethernet, storage, and optical modules.

“This technology richness means that every day I come to work, I feel I learn something new,” he says.

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Do optical DACs have a role in future coherent modems?

• A proposed optical digital-to-analogue converter (oDAC) concept offers several system benefits, including better signal performance, higher bit rates and lower power consumption.
• The oDAC design benefits coherent optics but can also be used in direct-detect designs. This article focusses on coherent optics.
• Coherent system vendors are aware of oDAC technology but it is not part of their current roadmaps. 

A 256-QAM constellation using a conventional coherent transmitter (left) and using the oDAC. Note there is no modulator loss (the full area is used) nor any optical warping using the oDAC. Source: Tomkos and Nazarathy.

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Ciena advances coherent technology on multiple fronts

• Ciena has unveiled the industry’s first coherent digital signal processor (DSP) to support 1.6-terabit wavelengths
• Ciena announced two WaveLogic 6 coherent DSPs: Extreme and Nano
• WaveLogic 6 Extreme operates at a symbol rate of up to 200 gigabaud (GBd) while the Nano, aimed at coherent pluggables, has a baud rate from 118-140GBd

Part 1: WaveLogic 6 coherent DSPs

Helen Xenos

Ciena has leapfrogged the competition by announcing the industry’s first coherent DSP operating at up to 200GBd.

The WaveLogic 6 chips are the first announced coherent DSPs implemented using a 3nm CMOS process.

Ciena’s competitors are - or will soon be - shipping 5nm CMOS coherent DSPs. In contrast, Ciena has chosen to skip 5nm and will ship WaveLogic 6 Extreme coherent modems in the first half of 2024.

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Nubis' bandwidth-packed tiny optical engine

• Nubis Communications has revealed its ambitions to be an optical input-output (I/O) solutions provider
• Its tiny 1.6-terabit optical engine measures 5mm x 7.5mm
• The optical engine has a power consumption of below 4 picojoule/bit (pJ/b) and a bandwidth density of 0.5 terabits per millimetre.
• “Future systems will be I/O with an ASIC dangling off it.”

Nubis Communications has ended its period of secrecy to unveil an optical engine targeted at systems with demanding data input-output requirements.

Dan HardingThe start-up claims its optical engine delivers unmatched bandwidth density measured in terabits per millimetre (T/mm) and power consumption performance metrics.

“In the timeframe of founding the company [in 2020], it became obvious that the solution space [for our product] was machine learning-artificial intelligence,” says Dan Harding, the CEO of Nubis.

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Teramount brings pluggability to co-packaged optics

Hesham Taha, the CEO and co-founder of Teramount, describes the last two years for his company as eventful.

"Many things have happened on many fronts," he says.

Teramount has developed a fibre assembly technology for designs integrating photonics and chips.

Hesham Taha

The start-up has raised $20 million in funding and has 30 staff. In addition, the company is recruiting staff experienced in manufacturing processes.

"The funding helps to support what we are working on today, which is manufacturing readiness," says Taha.

Taha also notes marketplace changes as when the rising interest in co-packaged caused some companies that had stepped out of silicon photonics to return.

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