Scientists from Boston University, University of California Berkeley, and Northwestern University have created the first system on a chip that integrates electronics, photonics, and quantum elements. This system uses a standard 45-nanometer semiconductor manufacturing process. The chip produces reliable streams of correlated photon pairs. These photon pairs are essential for quantum technologies like computing, communication, and sensing.
This advance allows for mass production of chips that act like factories for light in quantum states. The chip contains an array of small quantum light sources, each about one millimeter square. These sources rely on microring resonators, which are tiny ring-shaped structures on the chip that trap and manipulate light to generate the photon pairs. To work, the resonators must stay perfectly tuned to an incoming laser light that powers them.
Stabilizing the Quantum Sources
The resonators are very sensitive to changes in temperature or small manufacturing differences, which can disrupt the photon generation. To fix this, the researchers added built-in stabilizers. They integrated photodiodes, which are sensors that detect light, inside the resonators to monitor alignment with the laser. On-chip heaters and control circuits then automatically adjust the resonators to keep them in sync, even with heat changes or interference from nearby sources. The chip has twelve such sources that can operate together without issues.
This stabilization happens in real time on the chip itself, making the system predictable and reliable. The work required close work across fields like electronics design, light manipulation, and quantum measurements. The chip was made in a commercial complementary metal-oxide semiconductor platform. This process supports not only optical connections for artificial intelligence hardware but also complex quantum systems.
As a result, these chips could become building blocks for secure networks, advanced sensors, and quantum computers. The research shows that quantum photonic systems, which use light for quantum tasks, can be scaled up using existing manufacturing methods.
This research is published in Nature Electronics.