Scalable Deterministic Integration of Two Quantum Dots into an On-Chip Quantum Circuit

Abstract

Integrated quantum photonic circuits (IQPCs) with deterministically integrated quantum emitters are critical elements for scalable quantum information applications and have attracted significant attention in recent years. However, scaling them up toward fully functional photonic circuits with multiple deterministically integrated quantum emitters to generate photonic input states remains a great challenge. In this work, we report on a monolithic prototype IQPC consisting of two preselected quantum dots deterministically integrated into nanobeam cavities at the input ports of a 2 × 2 multimode interference beam splitter. The on-chip beam splitter exhibits a splitting ratio of nearly 50/50 and the integrated quantum emitters have high single-photon purity, enabling on-chip Hanbury Brown and Twiss (HBT) experiments, depicting deterministic scalability. Overall, this marks a cornerstone toward scalable and fully functional IQPCs.

Assessing the Alignment Accuracy of State-of-the-Art Deterministic Fabrication Methods for Single Quantum Dot Devices

“…Moreover, on-chip integration of QDs in nanobeam cavities/waveguides using the in situ EBL has recently been studied. The reported values show a CE of >29%, and a Purcell factor of ∼1.8 is preserved for up to a 50 nm QD offset Table summarizes the performance of the various photonic structures for different ranges of QD displacement.…”

“…The in situ EBL is known to feature high alignment accuracy of 30–40 nm and was initially employed for the development of different high-performance SPSs . Quite naturally, this advanced nanotechnology platform can also be used to define complex patterns, such as integrated quantum photonic circuits. ,, However, it is technically rather complex, as it requires the combination of low-temperature CL spectroscopy with low-temperature EBL in a single system. As still a further deterministic nanofabrication technology, the PL imaging approach has become very popular in recent years.…”

Dynamic Strain Modulation of a Nanowire Quantum Dot Compatible with a Thin-Film Lithium Niobate Photonic Platform

“…Quantum computation with on-chip photonic qubits has emerged as an important research area in quantum technologies. − In addition to the manipulation and detection of individual photons, achieving deterministic integration of single and indistinguishable photon sources is essential for the scalability and complexity of quantum photonic circuits. − Although more technologically challenging than monolithic approaches, − the heterogeneous integration of high-quality quantum emitters offers the possibility of producing more efficient devices and incorporating additional functionalities that would be difficult to achieve in single material systems. Toward this direction, III/V semiconductor quantum dots (QDs), − and defects in crystals , or in 2D materials − have been successfully transferred to Si, SiN, AlN, or LiNbO 3 while maintaining good performances as single photon sources.…”

Highly Indistinguishable Single Photons from Droplet-Etched GaAs Quantum Dots Integrated in Single-Mode Waveguides and Beamsplitters

“…Deterministic fabrication would also be beneficial to preselect QDs that are spatially and spectrally close for integration into the same MMI. 54 Nevertheless, the and resonant excitation of DEE GaAs QDs is an important step toward a high-quality on-chip source of single and indistinguishable photons with a small wavelength distribution and inherently short decay times.…”

“…A surface passivation could help in this regard, , as well as the integration into diodes , or deterministic fabrication , to maximize the distance to the sidewalls. Deterministic fabrication would also be beneficial to preselect QDs that are spatially and spectrally close for integration into the same MMI . Nevertheless, the integration and resonant excitation of DEE GaAs QDs is an important step toward a high-quality on-chip source of single and indistinguishable photons with a small wavelength distribution and inherently short decay times.…”