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OFC 2022 - A welcome return to normalcy

March 2022

LightCounting releases a research note on highlights and observations from OFC 2022

Broadcom’s switch ASIC equipped with co-packaged optics was the best live demonstration of the show. It featured a 25T ASIC with direct drive CPO in half of the ports and copper in the rest. Four pluggable modules containing uncooled external lasers powered the optics. The live demo was water cooled to minimize fan noise and maximize the impact. It was really impressive!

The eyes of Broadcom’s engineers were sparkling with pride and they have all the reasons to be proud. Broadcom surprised the industry in January 2021, when it disclosed plans to start shipping 25T switches equipped with CPO by the end of 2022. There were plenty of skeptics questioning such an aggressive timeline. LightCounting stated that Broadcom’s plans have to be taken seriously and we reiterate this statement now. The company is on target for shipping 25T/CPO switches by the end of 2022 and 51T/CPO by the end of 2023.

No photos were allowed in Broadcom’s demo area, but the chip looks just like the image Broadcom has advertised, shown in the figure below.

Yet, it will take many years for these new products to penetrate the market, despite numerous benefits. Our latest forecast for CPO was included in our December 2021 High Speed Cables, Embedded and Co-Packaged Optics Report. Reductions in power consumption of direct drive CPO are very appealing. The direct drive enables DSP-free optical engines, reducing power consumption by close to 50%. An additional 10% power savings comes from use of external lasers.

In contrast with direct drive and linear drive CPOs, Near Packaged Optics (NPO) requires a DSP integrated with the optical engine. It is a distant runner up in terms of power savings, as illustrated in the figure above.

OIF had a prototype of NPO on display in their booth and hosted a live demo of external laser small form pluggable (ELSFP) modules, designed to power NPO. The lasers were provided by AOI, Cisco, Lumentum, Innolume and O-Net.

Meta showed a design of their next generation switches based on a 51T ASIC with NPO ports around it inside a 4RU enclosure. The ports can be interconnected to the front panel pluggable transceivers with flyover cables, instead of using NPO. This approach enables Meta to continue using pluggables, while also testing NPO.

The OIF work may seem like a distraction to CPO, but it is important for suppliers to learn how to make optical chiplets and test their products in Meta’s datacenters. As we learned from COBO, many suppliers are willing to support the development efforts of one of the largest consumers of optical transceivers. Few of these projects will succeed in reaching high volume deployments, but all of them are steps in the right direction for the industry.

Luxtera (now Cisco) has been working with Meta on the development of on-board optical (OBO) engines for years now. They started with 100G modules, moved to 200G last year and must be working on an NPO approach now. Meta commented that SiPh-based OBO is a lot more reliable than InP lasers.

Marvell had a live demo on NPO in their booth, but LightCounting team has not had a chance to see it. The company is also following the OIF guidelines. Marvell presented Teralynx® switch platform with NPO electro-optics, integrated into a standard 1 rack-unit (RU) 32 port optical switch. The demonstration is the foundation for Marvell’s future 3.2T CPO platform for the 51.2T switch generation.

Intel is also supporting OIF NPO and plans to have it on the market in 2024. beefed up their resources with two acquisitions in early 2022: Optoscribe – a small company developing high density fiber coupling technology and Tower Semiconductor – a well-known SiPh/SiN foundry.

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