  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.
