Non-classical light sources operating at telecom wavelengths based on epitaxial quantum dots

Abstract: Quantum dots are an important resource for quantum communication because of their capability to generate various non-classical light states. Compared to other physical systems, they are advantageous in terms of single-photon purity independent of the source brightness. They offer the possibility for on-chip integration and compatibility with well-established semiconductor technology, including deterministic fabrication of photonic devices. Emission in the telecom bands is required to fully exploit their application potential as it provides compatibility with existing fibre network and maximizes transmission distance. Different material systems can be employed to achieve emission in the telecom spectral range: strain engineered InAs/GaAs, InAs/InP and GaSb/AlGaSb. Recent developments and achievements regarding emission of single photons and pairs of polarization-entangled photons, as well as remaining challenges in realization of ideal sources of non-classical light states based on quantum dots, will be reviewed and discussed.