Coherence in single photon emission from InAs/InP quantum dots in the telecom C-band

The ability of individual photonic qubits to interact via interference lies at the heart of many quantum networking applications. For their development, sources of highly coherent, indistinguishable photons are therefore crucial. Here, we investigate the noise sources that affect InAs/InP quantum dots and limit their coherence. We show that the droplet epitaxy growth mode leads to a quiet environment with 96% of exciton transitions having a coherence time above 100 ps, even under non-resonant excitation. Further, Hong–Ou–Mandel interference reveal a corrected two-photon interference visibility of 98.6±1.6% for these quantum dots, showing their potential for quantum networking applications.