Investigation of Purcell enhancement of quantum dots emitting in the telecom O-band with an open fiber-cavity

Abstract

Single-photon emitters integrated in optical micro-cavities are key elements in quantum communication applications. However, optimizing their emission properties and achieving efficient cavity coupling remain significant challenges. In this study, we investigate semiconductor quantum dots (QDs) emitting in the telecom O-band and integrate them in an open fiber-cavity. Such cavities offer spatial and spectral tunability and intrinsic fiber-coupling. The design promises high collection efficiency and enables the investigation of multiple emitters in heterogeneous samples. We observe a reduction of the decay times of several individual emitters by up to a factor of $2.46(2)$ due to the Purcell effect. We comprehensively analyze the current limitations of the system, including cavity and emitter properties, the impact of the observed regime where cavity and emitter linewidths are comparable, as well as the mechanical fluctuations of the cavity length. The results elucidate the path towards efficient telecom quantum light sources.