Start of funding 01.01.2020

Integrated quantum nanophotonic circuits

Prof. Dr. Kai Müller
Technische Universität München
Walter Schottky Institut

Prof. Dr. Marina Radulaski
University of California, Davis
Department of Electrical & Computer Engineering



The goal of this cooperation is to realize a novel scalable platform for integrated quantum nanophotonic circuits. Such a platform is of large interest in emerging technologies, for example in quantum information processing. The key of this proposal is to explore a hybrid platform that combines the best properties of two worlds – photonic circuits made out of silicon carbide (SiC), whose color centers would serve as emitters of quantum light, and superconducting nanowire single-photon detectors (SNSPDs). The nanophotonic circuits will be fabricated in the group of Marina Radulaski at UC Davis while the integration of superconducting detectors will be explored in the group of Kai Müller at TU Munich.

Final report:
Among all possibilities to implement quantum bits, photons are unique due to their scalability and ability to transmit quantum information over long distances. However, real world applications will require a scalable integrated platform for on-chip photonic quantum information processing, including the generation, routing, and detection of single photons. The goal of this project was to investigate the potential of silicon carbide (SiC) as a platform for such quantum photonic integrated circuits. To this end, the expertise of the group of Prof. Dr. Marina Radulaski at UC Davis on photonic circuits made of silicon carbide with integrated quantum emitters was combined with the complementary expertise of Prof. Dr. Kai Müller at TU Munich on integrated superconducting nanowire single-photon detectors (SNSPDs).

Specifically, a process map for the fabrication of SiC quantum photonic-integrated circuits with integrated SNSPDs has been developed and first steps towards its realization have been implemented. For the process map, it is crucial to ensure that fabrication steps necessary for one component of the integrated platform do not negatively impact on the other components. Superconducting niobium titanium nitride (NbTiN) films were grown and characterized on silicon carbide (SiC) samples and high-performing detector designs have been devised via simulations. This has been enabled by research visits between the groups and one joint workshop, and led to joint publications. [1]

[1] S. Majety, S. Strohauer, P. Saha, F. Wietschorke, J. J. Finley, K. Müller, and M. Radulaski. "Triangular quantum photonic devices with integrated detectors in silicon carbide." Materials for Quantum Technology 3, no. 1 (2023): 015004.