On-Chip Integration of Energy-Tunable Quantum Dot Based Single-Photon Sources via Strain Tuning of GaAs Waveguides

Self-assembled quantum dots (QDs) contribute versatile nonclassical light sources for implementing photonic quantum technologies. The recent success of integrating self-assembled QDs with various photonic architectures highlights their great suitability for efficient on-chip single-photon sources (SPSs). However, QDs suffer from large inhomogeneous broadening due to the random growth process, and their potential in practical integrated quantum photonic circuits can be harnessed only when precise tuning of the single-photon emission energy is achieved. Here we introduce a hybrid piezoelectric–semiconductor integration scheme to realize a GaAs quantum photonic chip (QPC) with energy-tunable QD-based SPSs. The hybrid chip is fabricated on a QD-containing GaAs nanomembrane that is transferred onto a single-crystal piezoelectric actuator. Deterministic single-photon emission from QDs is generated and routed along the highly confined GaAs waveguides. By varying the voltage applied to the piezoelectric actuator, optical properties of the QDs-based SPSs can be dynamically and reversibly manipulated by strain fields. Single-photon emission energy of QDs can be tuned in a broad range of 10.4 meV with a tuning rate of 6.4 pm·V^–1. The hybrid GaAs QPC with energy-tunable SPSs demonstrated here provides a feasible way toward the development of complex integrated quantum photonic circuits with improved scalability and functionality.