Lumiphase AG

Breakthrough in data communication

Data transmission over long distances is today mostly done using fiber optic cables. For this purpose, data from electronic systems has to be converted from electrical to optical signals, which are then transmitted at the speed of light through optical fibers and converted back to electrical signals at the receiving end. However, the transceiver modules that perform the conversion are expensive, power-hungry, and have reached their technological limits in terms of speed. Lumiphase AG, founded early in 2020, develops and manufactures a new type of optical semiconductor chips which form the core of a new generation of transceiver modules.

The engineers around the four company founders Stefan Abel, Lukas Czornomaz, Felix Eltes and Jean Fompeyrine have in fact developed a revolutionary technology to produce electro-optical semiconductor chips. These new chips will enable data transmission rates to be increased for years to come, allowing ever-larger amounts of data to be transmitted in a cost-effective and energy-efficient manner.

Transceiver modules are needed in large quantities in data centers, where optical transmission distances typically range from a few meters to 10 kilometers. However, significant amounts of data circulate not only within data centers; there are also significant amounts moving between different data centers via high-speed optical lines. Given the explosive growth in global data traffic, the technical challenge is to permit throughput rates required in the future in an energy-efficient and cost-effective manner.

Doubling performance

Data transfer technology is a closed ecosystem in which component manufacturers and operators of large data centers jointly set the maximum transfer rates as the standard. The current state of the art is 400 gigabits per second (Gbps); future performance increases will always be doublings of this value. The first Lumiphase products of will be components with 800 Gbps performance, but the same technology will be capable of 1.6 Tbit/s and more in the future.

What is Lumiphase’s particular innovation? In order to understand this achievement, it helps to first look at the currently used technical solution. Today, the transceivers utilized in the majority of data centers require communication chips based on silicon crystals (silicon photonics). However, the conversion of electrical to optical signals with this technology has reached its physical limits. The increase in the speed of the components inevitably leads to higher light absorption, which shortens the maximum achievable communication distance. In the last ten years, the possibilities based on silicon crystals have been exhausted. That is why new materials are now being sought.

Wafer-thin crystals

Lithium niobate crystals are a well-known solution for electro-optic modulation in transceivers. These have been used for decades in optical modulators for long transmission distances such as transatlantic links. They exploit the fast electro-optical Pockels effect. However, the components are several centimeters in size, and their specialized fabrication process makes them expensive to produce and impossible to scale to the necessary quantities of many millions of transceivers.

Wafer-thin crystals

Lithium niobate crystals are a well-known solution for electro-optic modulation in transceivers. These have been used for decades in optical modulators for long transmission distances such as Transatlantic links. They exploit the fast electro-optical Pockels effect. However, the components are several centimeters in size, and their specialized fabrication process makes them expensive to produce and impossible to scale to the necessary quantities of many millions of transceivers.

Lumiphase’s founders have spent ten years developing a barium titanate crystal with a thickness of just a few hundred nanometers. These thin films utilize the same electro-optical Pockels effect, but their efficiency in converting electrical to optical signals exceeds that of lithium niobate by a factor of twenty. Lumiphase’s innovation includes the manufacturing process for integrating thin layers of the barium titanate crystal into the established optical silicon photonics technology. What is more, it also involves novel designs of micro-meter sized optical components and complete circuits for communication chips.

The Lumiphase AG, which has its roots at IBM and ETH, and which today has more than 20 employees, is the only company across the globe that can offer such a process – from the production of the crystal and integration with silicon to the design of the components. It is therefore not surprising that, in addition to investors and funding, leading providers of communication solutions are also contributing to the development of the first products. Large data center operators in particular have a colossal need for next-generation transceiver modules. Having efficient and cost-effective data links might also make it possible to open up regions of the world where Internet access is still a luxury. This would help the three billion people who currently have no access to the Internet.

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