Linear Drive optics offers benefits, but challenges will limit deployment, says Cignal AI

Linear Drive optics can offer data center providers various benefits, namely reducing power by eliminating DSP functions from optics. However, Cignal AI cautions that “sizeable” business and technical challenges will limit architecture adoption.

Linear Drive reduces the power required by pluggable optics in routers and other equipment by eliminating the digital signal processor (DSP) and instead relying on the SERDES DSP (or PHY) in the switch chip for signal formatting.

The promise of Linear Drive stems from the fact that it eliminates the DSP on the pluggable optics. The DSP/PHY on the switch ASIC is used to directly drive an optical engine located on a pluggable that does not include retimers or DSPs, only linear amplifiers. Cignal AI said that by eliminating functionality, the power consumption for a Linear Drive system is not relatively as small as for Co-Packaged Optics (CPO – optical engines co-located with the switch ASIC). Still, it is much lower than traditional pluggable architecture and retains the benefits of pluggability.

Issues related to switch chip support, system design, interoperability, and timing will limit the overall size of the Linear Drive market opportunity. Some modules will be deployed in niche cases within homogenous hyperscale data centers.

Companies leading the charge of Linear Drive include Arista, Broadcom, Cisco, Credo, Eoptolink, Innolight, MACOM, Marvell, Nvidia and Semtech.

In the research firm’s newly released Active Insight report, “Linear Drive Market Opportunity,” only a fraction of Cignal AI’s 800GbE datacenter optics forecast will employ Linear Drive by 2027. It forecasts that less than 10% of our 800GbE datacenter optics forecast will use Linear Drive.

“There is tremendous excitement for Linear Drive architecture because it addresses the most challenging design problem for high-speed data center optics – power consumption – head on,” said Scott Wilkinson, lead analyst for optical components at Cignal AI. “But while researching the market opportunity, we found that market and technical challenges will limit Linear Drive optics to select hyperscale applications.”

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