Broadcom this week at OFC 2025 announced new additions to its 200G/lane DSP PHY portfolio for data center AI with the introduction of Sian3 and Sian2M, both focused on the connectivity requirements of AI/ML clusters. These innovations address the critical need for optimized power across both single-mode fiber (SMF) and short-reach multi-mode fiber (MMF) links in 800G and 1.6T optical transceiver applications.
Natarajan Ramachandran, Product Management & Business Development at Broadcom, told Fierce Electronics that as AI workloads continue to grow, the industry can’t let high power consumption become a limiting factor for cluster scalability, and that Broadcom’s vendor partners are asking the company to lower power consumption even further from the very competitive 28 watts of the Sian2 DSP PHY announced last fall.
“They want us to go down toward 20 watts,” Ramachandran said, “and the logic is that every AI cluster is part connectivity and part computation, and every time you're burning an additional watt in optical connectivity, you are taking away watts from computation.”
The Sian3 keeps low power consumption top of mind in the form of a 3nm 200G/lane DSP for sub-13W 800G and sub-23W 1.6T transceivers. The Sian2M is a 5nm 200G/lane DSP for sub-25W 1.6T SR8 transceivers.
Pluggable transceivers and their power consumption moved into the spotlight recently with Nvidia’s announcement that it is developing co-packaged optics to eliminate power-hungry legacy transceivers. These transceivers are likely to continue to play an important role in GPU interconnection for AI clusters for some time, but the demand for power efficiency improvements has never been more critical, and DSPs need to answer the call.
“According to our recent report Markets for PAM4 and Coherent DSPs, AI-infrastructure build outs are driving massive growth in PAM4 DSP shipments,” said Bob Wheeler, Analyst at Large, LightCounting, in a statement provided by Broadcom. “By 2028, we expect 1.6T optical transceivers will consume more than $1 billion worth of PAM4 DSPs, as next-generation 102T switch systems transition to 200G serdes."
Richard Huang, CEO of optical transceiver vendor Eoptolink Technology, added, "As the demand for high-speed, energy-efficient connectivity continues to rise, integrating Broadcom’s Sian3 and Sian2M into our transceivers allows us to deliver industry-leading performance with significant cost and power savings. By combining these advanced DSPs with our own engineering expertise, we are driving innovation across the ecosystem—enabling scalable, high-density optical connectivity that meets the evolving demands of next-generation AI infrastructure while lowering total cost of ownership.”
Here are more details on Broadcom’s most recent new product announcements:
Sian3 DSP
- Low power 3nm 200G/lane DSP for sub-13W 800G and sub-23W 1.6T transceivers
- 1.6T retimer PHY (BCM83628) and 800G gearbox PHY (BCM83820) options available
- Supports 212.5-Gb/s and 226.875-Gb/s data rates for InfiniBand and Ethernet
- Multiple FEC options, including Bypass, Segmented, and Concatenated FEC
- IEEE 802.3dj D1.3 compliant
- Integrated low-swing and high-swing laser drivers for SiP and EML modules
- Sub-75ns roundtrip latency for AI/ML
- Client-side SERDES supporting long-reach (LR) applications
- Crossbar support on client and line side
Sian2M DSP
- Low power 5nm 200G/lane DSP for sub-25W 1.6T SR8 transceivers
- 800G retimer PHY (BCM85834) supporting both 800G and 1.6T pluggable modules
- Multiple FEC options, including Bypass and Segmented FEC
- Integrated VCSEL driver
- Crossbar support
200G/lane Lasers
- Industry’s first 200G VCSEL, supporting the planned IEEE 802.3dj standards
- Broadcom VCSEL technology with >5 trillion field device hours and <1 FIT failure rate
- 200G EML in production, with millions of units shipped
Broadcom is sampling Sian3 and Sian2M to early access customers and partners, with Sian3 production ramping in the third quarter this year.