EAGER: Quantum Manufacturing: Monolithic integration of telecommunication-band quantum emitters in the 4H-SiC-on-insulator platform

Optically addressable spin defects available in solid-state materials are promising for scalable quantum information processing owing to their long coherence time for information manipulation and storage. In addition, individual color centers distributed in a quantum network can be entangled through photon facilitated interaction, which enjoys low-loss propagation in the existing fiber infrastructure.

As such, defect states such as nitrogen-vacancy (NV) centers in diamond received a lot of attention in the past two decades. Despite the efforts, the state of the art of NV centers has only achieved successful entanglement of a few quantum nodes, suggesting much work to be done for any practical applications. Recently, silicon carbide (SiC) emerged as another promising quantum material, as it hosts a variety of color centers in its polytypes including 3C, 4H and 6H.

Compared to NV centers in diamond, intrinsic defects in SiC exhibit similar spin properties while possessing unique integration and scaling advantages given that SiC is a CMOS-compatible material with favorable electrical and optical properties. The objective of this quantum manufacturing program is focused on the development of vanadium-based color centers in SiC that can be utilized as high-quality single-photon emitters in the telecommunication band.

Specifically, single vanadium defect will be deterministically introduced through optimized ion implantation and combined with various integrated photonic technologies in a low-loss 4H-SiC-on-insulator platform. Such monolithic integration of color centers with enabling chip-scale quantum technologies has the potential to transform quantum information processing in terms of reducing the device’s SWaP (size, weight, and power) and increasing available functionalities on the chip level.

This eventually will lead to a powerful solid-state quantum processor that plays an indispensable role in the scalable implementation of future quantum networks. Moreover, the proposed research activities are expected to produce excellent learning materials for the education of next-generation quantum engineers, and the research findings will be integrated into relevant courses and outreach programs.

The success of the project hinges on the development of methods and technologies that enable controllable introduction of vanadium defects to a low-loss 4H-SiC-on-insulator platform as a high-quality, telecom-band single photon emitter. For example, combining a single defect with a high-quality-factor microresonator and achieving strong mutual coupling is a proven technology to significantly reduce the defect’s optical lifetime and enhance its emission rate (Purcell effect).

In addition, low-loss integrated photonic technologies such as waveguides and microresonators make on-chip optical excitation and spectral filtering feasible, which leads to a compact system solution compared to approaches based on free-space optics. We will also explore the electrical tuning of the vanadium defect (Stark effect) and apply the Pockels effect to the SiC microresonator for frequency tuning and efficient electro-optic modulation.

If successful, we will develop a compact single-photon emitter that works in the telecommunication band with GHz-level emission rate, which can be readily interfaced with the classical information by employing a compact electro-optic modulator in 4H-SiC. Such a high-performance quantum source is expected to play a critical role in the next-generation quantum communication.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.