CEA-Leti Seeking Commercial Partners to Develop and Scale Disruptive Optical Interposer Technology for Chiplet Integration
As multi-chiplet designs become more prevalent, the efficiency of chiplet-to-chiplet interconnections is becoming a critical factor in defining competitive advantage. CEA-Leti, a prominent European technology research institute, has developed a groundbreaking solution that could transform this space: active optical interposers. These innovative interposers, part of CEA-Leti’s Starac project, were unveiled during Leti Innovation Days 2024 and promise to significantly enhance performance, reduce latency, and cut power consumption in chiplet systems.
Unlike traditional copper interconnections, Starac leverages silicon photonics to transmit data between chiplets, offering a higher performance solution while minimizing both latency and power draw. One of the standout features of this optical interposer is its ability to directly connect chiplets without the need for intermediate steps (or “hops”), which are typically required in conventional passive interposers. This results in faster communication and increased efficiency, especially as the complexity and number of chiplets in systems continue to rise.
The Starac demonstrator features a network-on-chip (ONoC) design with four chiplets, each containing 16 cores, alongside six electro-optical drivers. Its spiral waveguide structure, which is not feasible on passive interposers, allows for direct communication between chiplets, eliminating the delays often experienced in standard multi-chiplet setups. This capability is increasingly crucial for maintaining bandwidth, reducing latency, and managing power consumption in modern multi-chiplet systems-in-packages (SiPs).
While CEA-Leti has successfully showcased the potential of this optical interposer technology, the institute is a research entity and does not engage in production. As a result, CEA-Leti is actively seeking commercial partners to further develop and commercialize the Starac demonstrator. The institute is looking to collaborate with system-in-package designers and foundries to refine the manufacturing process and scale the technology for mass production.
Building the Starac demonstrator presented numerous challenges, as it required developing entirely new manufacturing techniques that have yet to be implemented at scale. However, CEA-Leti’s efforts represent a significant step forward in the use of photonics for more efficient, scalable communication solutions within SiPs.
The future of optical interposers appears promising, and with the right commercial partnerships, this technology could soon find its way into high-volume production, paving the way for faster, more efficient multi-chiplet systems.
