NcodiN or improving interconnects
As demand for computing power continues to rise, especially for AI, chips must become ever more efficient. The miniaturisation of transistors, the fundamental component of microelectronics, is reaching its limit, as is the use of copper to transmit information between the different parts of a processor. To overcome these challenges, the start-up NcodiN is proposing replacing standard electronic interconnects with optical links. This is based on a breakthrough innovation: the world's smallest laser integrated on silicon.
After completing his thesis at the Centre for Nanoscience and Nanotechnology (C2N - Univ. Paris-Saclay/National Centre for Scientific Research (CNRS)/Univ. Paris-Cité) in 2020, Francesco Manegatti invented new interconnect technology for AI processors. "This involves a nanostructuring of semiconductors typical of photonics, making it possible to design the world's smallest laser integrated on silicon," explains the researcher. In 2023, he founded the start-up NcodiN to develop this technology, alongside Fabrice Raineri (his former thesis supervisor, now a professor at the Nice Institute of Physics) and Bruno Garbin, a post-doctoral student at C2N when the entrepreneurial project was launched.
Francesco Manegatti continues: "When we started NcodiN, we had witnessed the explosion in artificial intelligence, particularly generative AI. In this context, the use of multiple chips in the design of next-generation processors was becoming increasingly popular, along with a growing need for performance to interconnect units efficiently, quickly and with minimum power loss. The best way to do this is using light, based on the same principle as fibre optics."
Since its launch, NcodiN has raised 4.2 million euros in pre-seed financing via four European venture capital firms: Elaia, Earlybird, OVNI Capital and Verve Ventures. This enabled it to demonstrate its breakthrough technology at the end of 2024. The start-up is currently based at C2N in Palaiseau (Essonne), but will soon be moving to new premises on the Saclay plateau. It was incubated by Agoranov in Paris and accelerated by Wilco and 21st by CentraleSupélec. It also received support from the Intel Ignite international accelerator in Munich, Germany. NcodiN now employs twenty people.
Optics for data transmission
"The advantage of optics lies in its physical properties, it can cover longer distances with far greater energy efficiency," explains Francesco Manegatti. In a context where processors are constantly expanding to accommodate more chips, these characteristics are increasingly important. These units will soon have to be connected over several centimetres, a seemingly short distance, but one that results in significant energy loss due to the high performance demands of AI processors.
Light is therefore the most efficient way to interconnect them. "We've made a communication chip, with a highway system to link all the components together within a processor. The key to our success is that we have developed a highly compact and densely integrated component that converts electrical signals into light and vice versa," adds the co-founder. In terms of the transmitter, the component (a nanolaser) captures the electrical signal, converts it into light and then sends it to the receiver through a silicon waveguide. The receiver, a photodetector, picks up the signal and transforms it back into an electrical message.
The start-up's technology is currently at level 4-5 on the TRL (Technology readiness level) scale. Industrialisation is set to begin in summer 2025, with high-volume production and marketing scheduled for early 2029. "We're working with leading manufacturers to optimise the performance of our products and create the first market-ready version. We're now in a rapid growth phase and aiming to reach certain milestones that were planned for the coming years ahead of schedule. We had originally intended to launch a new funding round towards the end of 2025, but many investment funds are knocking on our door right now," explains the co-founder.
Rethinking the approach
"Traditional copper interconnects are limited in terms of bandwidth and the distance covered while maintaining performance. Manufacturers are all agreed on the need for optical technologies to complement copper for high-performance applications," explains Francesco Manegatti. The start-up's competitors are mainly based in the United States and are designing optical technologies using industry standard components developed between ten and twenty years ago and still manufactured in photonics manufacturing facilities.
"Any optical solution can address the growing bandwidth requirements of AI computing systems. The question is: at what price? There's a huge difference between one approach and the other, and the industry standard components aren't necessarily compatible with this approach," comments the co-founder. These components do not necessarily have the same specifications as today's processors, as they were developed for longer distances and different applications. "Manufacturers want all the power supplied to the processor to go towards computing, and as little as possible lost to interconnects. But when well-established photonic solutions are used, less than 50% of the power goes to computing, the rest is lost to interconnects. We've considered our approach in order to address this issue and that's why we're introducing innovations at the component level," explains Francesco Manegatti.
With NcodiN’s solution just 3% to 5% of the power goes to interconnects. To achieve this, the start-up uses standard materials and III-V indium phosphide (InP) semiconductors integrated on silicon. The co-founder adds: "Our manufacturing processes are standard, but the new design we've developed allows us to minimise the dimensions of the components."
Reducing the energy cost of AI
NcodiN is primarily targeting the AI market, the epicentre of which lies in the United States. Its customers are processor vendors such as Intel and Nvidia. However, the value chain also extends to Taiwan, which specialises in electronic chips, and more broadly across Asia for assembly.
Data centres require an enormous amount of energy. According to the International Energy Agency, they consume around 5% of the world's energy and by 2030, forecasts estimate that this figure will rise to 20%. At present, interconnects are a major contributor to this energy usage. "Optics can provide something unique in terms of reducing the ecological impact by replacing copper. Our solution could cut data centre CO2 emissions by several tonnes. It won't happen overnight, but it will have a major impact, " enthuses Francesco Manegatti.