Broadcom has debuted two optical networking chips that are specially designed to handle the challenges of data transmission for AI workloads in data centers.
Dubbed Sian3 and Sian2M, the new digital signal processors (DSPs) expand on Broadcom’s 200G/lane DSP PHY line of processors and support optimized connectivity in high speed optical networks.
The vast amounts of data needed for today’s AI applications is prompting datacenters to boost their networks’ bandwidth. Artificial intelligence (AI) workloads demand more interconnect density. Datacenters have long used optical networks, yet even these high-speed data highways need to be pushed to greater connectivity to enable AI’s required scalability.
Broadcom touts its Sian3 and Sian2M as enabling previously unseen speeds and cost efficiency in the service of AI workloads.
“Broadcom’s new Sian2M and Sian3 chipsets are an important advancement in the growing power costs for datacenters,” said Tom Hollingsworth, events lead for Tech Field Day, The Futurum Group. “By lowering the power consumption of high-speed fiber optic links, Broadcom can stem the tide of growing power consumption in the modern AI-driven datacenter. In addition, lower power consumption leads to lower heat generation which reduces strain on the datacenter cooling infrastructure. Adoption of these new chipsets should drive upgrades to 800 GbE and 1.6 TbE switching in the near term.”
Optical networks use light signals to transmit data at rates similar to the speed of light, yet servers require electric signals. So a data center uses pluggable transceivers to transform electricity into light and then back again. Both the Sian2M and Sian3 chips power these pluggable transceivers, and Broadcom claims they do so at top speeds. These DSPs are capable of 1.6 terabits of data transmission per second, an incredibly fast rate that’s at the upper level of what’s currently possible.
The Sian2M, an iteration of the Sian2 product unveiled last September, is designed for lower power usage over Multi-Mode Fiber (MMF), which is a transmission technology built to support fiber optic cables that link over short distance like within a datacenter or campus. MMF connectors are designed with multiple strands of glass that can transmit data using light beams of various wavelengths, which increases capacity for short-distance transmission.
The Sian2M includes a Vertical-Cavity Surface-Emitting Laser (VSCEL) emitter for creating the light beams that transmit data across fiber optic networks. This streamlines the hardware infrastructure needed because the attached transceiver equipment doesn’t require a stand-alone laser.
The Sian2M uses a five-nanometer design. Broadcom claims the Sian2M builds on its track record in optical interconnects, which by the company’s count has deployed over 50 million channels of 100G VSCELs in AI networks.
The Sian3 chip uses Single Mode Fiber (SMF) technology, which transmits data over long distances (up to 62 miles without repeaters), and so is ideal for remote cloud-based AI applications. SMF is also a popular choice to send data between far-flung locations within a datacenter. Broadcom touts the Sian3 as delivering the industry’s lowest power consumption for 800G and 1.6T optical transceivers utilizing SMF.
The Sian2M and the Sian3 are built with Forward Error Correction (FEC) technology, which adds redundant error-correcting code to data in transmission to enable the receiving unit to correct problems without the delay of a repeated data transmission.
As an additional boost to the chips’ error protection, they both contain a retimer module that will intercept problematic data and replace it with an error-free transmission.
According to one market analyst, the speed and data transfer of these 1.6T chips will drive significant spend for AI deployments. “According to our recent report Markets for PAM4 [Pulse Amplitude Modulation 4-level] and Coherent DSPs, AI-infrastructure buildouts are driving massive growth in PAM4 DSP shipments,” said Bob Wheeler, Analyst at Large, LightCounting. “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.”
