AI blew up demand for data center computing power over the last couple of years, and now it is doing the same for demand for bandwidth between the chip clusters that are enabling the AI boom.
To handle the quickly ramping need for more intra-data center bandwidth, data center operators are getting ready to deploy 1.6 Tbps optical transceivers supporting 200 Gbps per lane between clusters. With that in mind, Broadcom came to the European Conference on Optical Communication (ECOC) in Frankfurt, Germany this week with its latest Sian PAM-4 DSP PHY device in hand. The Sian2 features 200G/lane electrical and optical interfaces to augment the 100 Gbps electrical and 200 Gbps optical interfaces that the first-generation Sian DSP already supports. Both the Sian and Sian2 DSPs enable pluggable modules with 200G/lane interfaces that are foundational to connect next-generation AI chip clusters, according to Natarajan Ramachandran, Product Management & Business Development at Broadcom.
Ramachandran also told Fierce Electronics that the Sian2, now sampling to early-access customers, has arrived none too soon for Broadcom’s customers.
“We think that this market will take off as early as January 2025,” he said. “Even though we are announcing the product at ECOC this week, we have had this product since May, and we are in a huge rush. Our biggest end customer is pushing us to get this product into production.”
The company’s sense of urgency is appropriate, according to an analyst that provided comment for Broadcom’s press release. “AI market leaders will start ramping optical modules using 200G/lane in 2025,” stated Dr. Vlad Kozlov, CEO and Chief Analyst at LightCounting. “There is a race for dominance in AI fueling a demand for delivery in excess of 1 million units of 1.6T optical transceivers within the first 12 months. We have never seen new products ramping at such rate.”
Just as growing AI model sizes are requiring greater compute performance, they also are speeding up the timeline for networking upgrades to links with higher bandwidth, lower latency, and greater resiliency. This necessitates the migration from the 400G/800G links with 100G/lane optics being used in AI clusters today to 800G/1.6T links with 200G/lane optics. Broadcom’s Sian2 and Sian DSPs are optimized for 800G and 1.6T optical module platforms made by Broadcom partners like InnoLight and Eoptolink, two firms it is coordinating Sian2 demonstrations with at ECOC.
Here are some product details for the Sian2:
- Low power 5nm 200G/lane DSP solution enabling sub-28W 1.6T transceivers
- Supports 800G and 1.6T pluggable modules
- Support for both 212.5-Gb/s and 226.875-Gb/s data rates for InfiniBand and Ethernet applications
- Support for multiple FEC options including Bypass, Segmented and Concatenated FEC
- Built-in low-swing and high-swing laser driver for both SiP and EML based optical modules
- Sub-80ns roundtrip (Ingress + Egress) latency for AI/ML applications
- Crossbar support for ease of transceiver design