LIGHTWAVE Online: June 17, 2021

Avicena touts LED-based LightBundle optical interconnects for chip-to-chip communication

The company’s LightBundle leverages microLED light sources and multicore fibers to create highly parallel interconnects that Avicena sources say can enable chip-to-chip communications at distances up to 10 m

AUTHOR: Stephen Hardy

Mountain View, CA, based startup Avicena Inc. has announced an optical interconnect based on technology from the imagery and display worlds. The company’s LightBundleTM leverages microLED light sources and multicore fibers to create highly parallel interconnects that Avicena sources say can enable chip-to-chip communications at distances up to 10 m.

At the heart of the LightBundle is the company’s Cavity-Reinforced Optical Micro-Emitters (CROMEs), based on GaN microLEDs, according to Chris Pfistner, who works in marketing and business development with Avicena. Such visible light emitters are commonly used in the display arena, but typically can transmit less than 1 Gbps of information. Avicena has developed a way to boost that output to approximately 10 Gbps, Pfistner says. The blue CROMEs are bonded to CMOS in a highly parallel array alongside arrays of silicon photodetectors grown directly in CMOS. The technology is capable of producing 10 Tbps per square millimeter at a power efficiency of less than 0.5 pJ/bit, Pfistner asserts. The CROME emitters can operate at ASIC temperatures, meaning they can serve reliably as internal laser sources for co-packaged optics without cooling.

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Avicena Post-Deadline Paper at OFC 2021

OFC 2021 Post-Deadline Paper, Friday, 11 June 08:00 – 10:00 PDT

Wide and parallel LED-based optical links using multi-core fiber for chip-to-chip communications

B. Pezeshki et al.

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Press Release

Avicena unveils LightBundleTM, a chip interconnect technology with dramatically lower power consumption and higher bandwidth density

Highly parallel optical links with power efficiency of 0.1pJ/bit, bandwidth density of 10Tbps/mm2 and reach of up to 10m promise to smash current interconnect bottlenecks in distributed compute systems

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MOUNTAIN VIEW, CA — June 8, 2021 —

Avicena Inc., a privately held company in Mountain View, CA, today unveils LightBundleTM, a highly parallel optical interconnect technology targeting up to 10 meters reach for chip-to-chip interconnects in distributed computing, processor-to-memory disaggregation, and other advanced computing applications. LightBundleTM is based on arrays of novel GaN high-speed micro-emitters, leveraging the microLED display manufacturing ecosystem, and is fully compatible with high performance silicon ICs.

Interconnects are becoming the key bottleneck in compute and network systems. Highly variable workloads are driving the evolution of densely interconnected, heterogeneous, software-defined clusters of CPUs, Graphical Processing Units (GPUs), Data Processing Units (DPUs) and shared memory blocks. Exploding Artificial Intelligence (AI) and Machine Learning (ML) workloads are exemplary of emerging applications driving an accelerating need for interconnects with extremely high density, low power consumption and low latency.

We have developed very high-performance optical transmitters based on emitter technology from the display industry. These innovative devices would have been impractical just a few years ago. Our optimized devices and materials support 10Gbps links per lane over -40°C to +150°C temperature with excellent reliability. — Bardia Pezeshki, Founder & C.E.O.

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Avicena at OFC 2021 Rump Session

OFC 2021 Rump Session, Wednesday, 09 June 06:00 – 08:00 am PDT

Did the Optics Industry Blunder by Switching Intra-Datacenter Links from NRZ to PAM4?
Will More DSP like PAM6 and Coherent Follow, or Will WDM and Parallel Save the Day?

Session Organizer and WDM Team Captain:  Chris Cole, II-VI Incorporated, USA
WDM Team Provocateurs: Shigeru Kanazawa, NTT, Japan; Boris Murmann, Stanford University, USA: Chris Pfistner, Avicena Tech, USA; Peter Winzer, Nubis Communications, USA

Session Organizer and DSP Team Captain:  Ilya Lyubomirsky, Marvell, USA
DSP Team Provocateurs:   Yi Cai, ZTE, USA; Dan Sadot, Ben Gurion University, Israel; Henry Sun, Infinera, Canada; Xiang Zhou,Google, USA

Description from WDM Team:
PAM4 was chosen for bandwidth limited electrical channels by the IEEE Ethernet Group in 2012. Modulation format for 50G λs was debated by the IEEE in 2015. Shannon provided clear guidance to stick with NRZ because the optical channel is limited by SNR and not bandwidth. Unfortunately, because the optics industry is the tail on the IC industry dog, PAM4 was chosen to reuse ASIC SerDes technology already in development. This unnecessarily and permanently locked in lower SNR and higher power for optical links. PAM4 50G λs will ship in the millions despite availability of mature 50GBaud technology which enables 50G NRZ λs. Shannon was again ignored by the IEEE for 100G λs and appears likely to be ignored for 200G λs. However, emerging applications not tied to Ethernet are returning to communication theory fundamentals and defining higher channel count lower-order modulation WDM and Parallel links.

Compound Semiconductor: June 2021

Compound Semiconductor: June 2021

Easing the chip-to-chip communication bottleneck by leveraging microLED display technology

High-speed optical emitters derived from GaN-based microLED displays can move data at much higher density and lower power than copper, bringing optical connections to the centimetre scale


MOST OF THE ENERGY consumed in computing systems is not in the computation, but in moving data, and the longer the distance, the greater the challenge in terms of energy and density. At longer length scales, fibre optic links have replaced copper, but at short distances the significant amount of energy required to convert data back and forth between photons and electrons makes optical interfaces prohibitive.

Although it may raise a few eyebrows, at these shorter length scales, optimized optical emitters derived from GaN microLEDs could be a promising candidate for optical communications by leveraging their success in the display industry. Such a move could transform the $400 billion computer hardware industry and enable entirely new architectures for parallel computing, machine learning, and processors.

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