Silicon photonics—what does it involve?

Using microelectronics methods, lithographically distinct components and complete photonic systems can be printed onto silicon wafers—fiber optic cables, lenses, splitters, optical amplifiers, phase modulators, polarization transformers, etc.

This enables the integration of laser and sensor systems or photonic integrated circuits (PICs) on chips.

The problem of the rapid increases in energy demand and heat generation in data centers is an important driver for silicon photonics. While electronic cables, circuits and chips require a lot of energy for each data transfer, which mostly ends up as useless waste energy, optical data transmission is far more energy-efficient—fiber optic cables show almost no thermal reaction at even the highest data rates.

Challenges arise, for instance, when connecting the miniaturized, almost 100 nanometer-thin waveguides on the chips to normal optical fibers with diameters in the double-digit micrometer range; or ultrapure materials for which atom-thin optical 2D functional layers on the chips often need to be developed.

Today, researchers are working on compact LiDAR-on-a-chip systems without moving parts. Complex receiver and transmitter systems with dozens of lasers, modulators, wave lockers, detectors, etc. can be accommodated on chips no larger than a fingernail. This doesn’t just save on costs and space, it also leads to robust, functionally superior system designs. A wide range of photonic chips can be achieved on the same waver. It is now possible to fit well over 1,000 optical components on one chip, and this may rise to tens or hundreds of thousands of components per chip as nanophotonic methods and components continue to be developed.

According to Yole Développement, the market volume of silicon photonics will rise from 400 million to 1.4 billion USD by 2025.

We recommend watching the introductory lecture, “The Revolution of Silicon Photonics” by pioneering researcher Michal Lipson at the New York Academy of Sciences and the in-depth version of the lecture, which she held at the 2019 World of Photonics Congress in Munich.

There is also an excellent overview of integrated photonics in general and silicon photonics specifically in a lecture by Belgian expert Dries Van Thourhout.