  We present a design study of quantum light sources based on hybrid circular
Bragg Gratings (CBGs) for emission wavelengths in the telecom O-band. The
evaluated CBG designs show photon extraction efficiencies > 95% and Purcell
factors close to 30. Using simulations based on the finite element method, and
considering the influence of possible fabrication imperfections, we identify
optimized high-performance CBG designs which are robust against structural
aberrations. In particular, full 3D simulations reveal that the designs show
robustness regarding deviations of the emitter position in the device well
within reported positioning accuracies of deterministic fabrication
technologies. Furthermore, we investigate the coupling of the evaluated hybrid
CBG designs to single-mode optical fibers, which is particularly interesting
for the development of practical quantum light sources. We obtain coupling
efficiencies of up to 77% for off-the-shelf fibers, and again proof robustness
against fabrication imperfections. Our results show prospects for the
fabrication of close-to-ideal fiber-coupled quantum light sources for long
distance quantum communication.
