China makes new advances in photonic quantum chip research

A multidisciplinary team in China has created a hybrid photonic quantum chip that integrates quantum dots with lithium niobate, enabling highly efficient single-photon generation, precise spectral tuning and a major leap toward scalable quantum networks and future quantum internet systems.

A consortium of Chinese researchers has unveiled a next-generation photonic quantum chip that could significantly accelerate progress toward scalable optical quantum technologies. Developed by teams from the Shanghai Institute of Microsystem and Information Technology (SIMIT), Sun Yat-sen University and the University of Science and Technology of China, the chip merges deterministic quantum-dot single-photon sources with low-loss lithium niobate thin films—an approach designed to overcome key barriers in today’s mainstream photonic chips.

Current optical quantum processors rely largely on probabilistic photon generation, which limits efficiency and makes multi-photon state preparation extremely difficult. Solid-state quantum emitters, by contrast, offer deterministic and highly efficient single-photon output, but integrating them at scale has been hindered by spectral inconsistencies and lack of robust hybrid-integration techniques. The new chip directly addresses these limitations.

Precision integration and on-chip tuning mark major technological leap

The team demonstrated a high-accuracy micro-transfer-printing method capable of placing up to 20 quantum-dot emitters onto a lithium niobate platform with nanometer precision. This forms the largest hybrid photonic quantum chip reported to date based on deterministic emitters. The researchers also engineered a localized stress-tuning technique—enabled by ferroelectric-domain control in lithium niobate—that allows wide-range, reversible spectral tuning of individual photon sources at cryogenic temperatures with extremely low power consumption.

These advances allowed the researchers to achieve on-chip quantum interference between spatially separated emitters, a core requirement for building functional multi-photon quantum circuits and scalable quantum networks. The integration density reached 67 emitters per millimetre, suggesting that centimeter-scale chips could eventually support more than 1,000 quantum channels.

Paving the path toward scalable quantum networks

The hybrid design opens new possibilities for combining lithium niobate’s high-speed electro-optic capabilities with deterministic photon sources to enable fast on-chip routing, entanglement distribution and potentially fault-tolerant linear optical quantum computing. With microwatt-level power needs and compatibility with superconducting detectors, the architecture offers a viable roadmap for future quantum internet infrastructure.

Researchers say the next phase will involve exploiting the material’s electro-optic strengths to support rapid switching and more complex quantum-logic operations, laying essential groundwork for practical optical quantum technologies.