The largest scale: Jin Xianmin's team of Shanghai Jiaotong University achieves monolithic integration of 128 identical quantum light source chips
Recently, the team of Jin Xianmin from Shanghai Jiaotong University experimentally realized an array chip integrating 128 isotonic quantum light sources in a single chip. 128 Identical Quantum Sources Integrated on a Single Silica Chip" was published in Physical Review Applied, the authoritative journal of physics in the United States, and was selected as "Editors' Suggestion".
High-performance integrated quantum light sources are key modules in quantum information science and technology. In recent years, many research teams at home and abroad have devoted themselves to improving various performance indicators of a single quantum source based on different platform technologies. However, overcoming the performance fluctuations between different quantum sources from a macroscopic perspective is rarely studied. In fact, the difference in performance between light sources hinders the construction of larger-scale Hilbert spaces, making it impossible to solve more complex and high-dimensional computational tasks. Therefore, addressing the inhomogeneity in the fabrication of quantum light sources is a major challenge.
Professor Jin Xianmin's team has been devoted to the research in the field of photonic integration for many years. By actively controlling the interaction process of light and matter, it has mastered the sensitive and stable birefringence control ability, and can integrate hundreds of light sources without additional auxiliary processes. The birefringence wander is controlled below 5%, and the emitted spectral wander is below 1 nm.
The research team separately characterized the spectral properties of the signal light and idler light between all 128 quantum sources, and performed 16,384 measurements and analyses each. Among them, the minimum spectral overlap value of signal photons is 0.943±0.007, and the minimum spectral overlap value of idler photons is 0.963±0.004. Compared with the previous record-keeping team’s 6nm spectral flutter, the birefringence regulation accuracy is significantly improved.
The research team verified the indistinguishability between the on-chip integrated sources through Hong-Ou-Mandel interference between a series of quantum sources, and all the experimental values measured were above 90%, proving the stable and continuous quantum source processing capability. The brightness of the light source can easily reach the order of megahertz, and in addition, discrete-variable or continuous-variable encoding can be achieved by switching different pumping schemes.
The above research results realize the scalable generation of identical quantum source arrays, which, combined with on-chip quantum devices and logic gates, will enable the practical application of large-scale all-on-chip quantum processors.
The research team would like to thank the major projects of the Shanghai Municipal Science and Technology Commission, the key projects of the National Natural Science Foundation of China, the National Key R&D Program, the Shanghai Municipal Education Commission, and "Turing Quantum" for their strong support. Ren Ruojing, Ph.D., from the Research Center for Integrated Quantum Information Technology, Shanghai Jiao Tong University is the first author of the paper, and Professor Jin Xianmin is the corresponding author of the paper.
Paper link:https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.16.054026
