OFC 2023: Broadcom launches 51.2T CPO optical engine

Technologies and Products

Chipmaker Broadcom, will be demonstrating a prototype of its Tomahawk® 5 based 51.2T  “Bailly” CPO system at OFC 2023, along with a fully functional Tomahawk® 4 based 25.6T “Humboldt” CPO system debuted at CIOE in September 2022. Both units were developed as a result of a strategic partnership with Tencent Holdings and are aimed at the hyperscale data centre market.

The Tomahawk® 5-based 51.2T Bailly CPO is Broadcom’s first all-CMOS EIC, and includes a very low power TIA, as well as a monolithically integrated optical MUX/DEMUX on the PIC. Broadcom has increased optical engine bandwidth from 3.2T on Humboldt to 6.4T on the Bailly to deliver an all-optical 51.2 CPO switch solution. In the process, the company expects to reduce optical interconnect power even further to 5.5W per 800G, meaning the Bailly CPO solution can deliver double the bandwidth of a 25.6T standard solution without increasing system power consumption. The large reduction in power coupled with the very high escape density of CPO will allow system vendors to design the smallest possible form factor for a 51.2T switch appliance.

The Tomahawk® 4-based 25.6T Humboldt CPO system will operate with 128 lanes of 100G DR connectivity emerging from the ASIC substrate from four 3.2Tb/s integrated optical engines. The full system operates with half the switch lanes escaping optically and the other half electrically. Each optical engine uses only two pieces of silicon – a PIC and an EIC packaged together at wafer scale pitch matched to the SerDes bumps inside the Tomahawk® 4. The system demonstrates optical interconnect power consumption of less than 7W per 800G, a more than a 50 percent improvement from traditional pluggable modules.

Manish Mehta, vice president of marketing and operations with Broadcom’s Optical Systems Division told Optical Communications, “Our Bailley device has become very interesting to hyperscalers, and we announced the partnership with Tencent last year in order to take this technology into actual network deployments. By bringing down the power consumption of the device, we’ve made it smaller and so it can have a lot more ventilation. On the front panel, there’s a lot less cost on the optics, because we’ve transitioned from discrete lasers and DSPS to just a few integrated pieces of silicon, so we’ve also reduced the cost of power in the network as well, and we’re going to be demonstrating that we can have all 128 100 Gig lanes operating error-free on this device.  Also, I think, another very critical element of this is we’re designing a system that’s fully interoperable with any Ethernet 100 Gig link. So this device sitting in the network can interface with any optic that exists on a NIC card or another switch from Broadcom with an optic attached to that appliance, or a switch from any other vendor developing IEEE compliant optics.”

Mehta added, “The circuitry inside existing optical transceivers has become quite complex, it’s become power hungry and expensive, and the assembly of these transceivers is still highly discreet and manual in nature. Millions of these optical transceivers are consumed by hyperscalers every year, and the cost dwarfs the actual spend on for example switch silicon. It’s unsustainable that the existing paradigm of discrete lasers, power hungry DSPs within an optical transceiver can continue given the increasing inside data centre east-west traffic requirements, emerging AI and ML backend clusters and standard networking in office CPUs.”

For more information, visit www.broadcom.com