Purdue advances scalable quantum PICs
Silicon nitride photon sources and single-photon switching offer new pathways towards scalable quantum photonic circuits.
Researchers at Purdue University are advancing the development of quantum photonic integrated circuits (PICs) through innovations in single-photon generation, optical switching and quantum coherence control.
Led by Vladimir Shalaev and Alexandra Boltasseva, the research addresses key challenges in scaling photonic quantum computing, including the reliable generation and manipulation of individual photons as quantum bits, or qubits.
The team has developed silicon nitride platforms capable of emitting single photons at room temperature.
By engineering atomic defects within nanoscale pillars, the researchers have demonstrated greater control over the placement and density of photon emitters, supporting more uniform and scalable fabrication of quantum photonic devices.
“Single photons are the building blocks of quantum photonics. The biggest challenges in scaling up a quantum photonic integrated circuit have to do with creating good single-photon sources,” said Shalaev.
The researchers have also demonstrated a single-photon optical switch that exploits optical nonlinearity in silicon.
A single control photon triggers an electron avalanche, changing the material’s refractive index and enabling the switching of a separate optical beam.
The approach offers a potential building block for information processing in quantum PICs.
Alongside hardware development, the team is investigating machine learning techniques to predict and mitigate quantum decoherence.
The researchers have developed a framework to anticipate spectral diffusion, a phenomenon that causes emitted photons to shift in frequency and reduces their indistinguishability.
“Decoherence is seemingly random, but in fact there is a certain pattern that can be recognized. This study takes an important step in identifying such a pattern using machine learning,” said Boltasseva.
The research is part of Purdue Computes, a university-wide initiative advancing computing, artificial intelligence, quantum science and semiconductor innovation.
Together, these developments could support the fabrication of more reliable and scalable quantum photonic integrated circuits, paving the way for next-generation quantum computing and optical information processing systems.
