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

Integratedquantum photonic circuits (IQPCs) with deterministicallyintegrated quantum emitters are critical elements for scalable quantuminformation applications and have attracted significant attentionin recent years. However, scaling them up toward fully functionalphotonic circuits with multiple deterministically integrated quantumemitters to generate photonic input states remains a great challenge.In this work, we report on a monolithic prototype IQPC consistingof two preselected quantum dots deterministically integrated intonanobeam cavities at the input ports of a 2 x 2 multimode interferencebeam splitter. The on-chip beam splitter exhibits a splitting ratioof nearly 50/50 and the integrated quantum emitters have high single-photonpurity, enabling on-chip Hanbury Brown and Twiss (HBT) experiments,depicting deterministic scalability. Overall, this marks a cornerstonetoward scalable and fully functional IQPCs.