GaSb-Based 1.5 μm Quantum Dot Emitters for Quantum Photonic Integration and Communication

Solid-state single and entangled photon emitters linked coherently over long distances with optical fibers enable a new generation of quantum-based communications networks. Currently, epitaxial semiconductor quantum dots (QDs) pave the way for a scalable approach to fabricating deterministic non-classical light sources that can be integrated with other photonic or electronic components in miniaturized form. A remarkably successful approach for the QD growth for quantum photonic applications is based on filling the nanoholes created by droplet-etching involving materials from the GaAs/AlGaAs alloy system. In particular, such
$\text{GaAs}$
QDs have enabled non-classical light sources providing state-of-the-art performance in terms of photon indistinguishability and entanglement. [2–5] However, this material system is restricted to the 680–800 nm wavelength range owing to its limited direct band gap range, and thus is not suitable for long-haul transmission over optical fibers or integration with Si photonics.