Single- and Twin-Photons Emitted from Fiber-Coupled Quantum Dots in a Distributed Bragg Reflector Cavity.

In this work, we develop single-mode fiber devices of an InAs/GaAs quantum dot (QD) by bonding a fiber array with large smooth facet, small core, and small numerical aperture to QDs in a distributed Bragg reflector planar cavity with vertical light extraction that prove mode overlap and efficient output for plug-and-play stable use and extensive study. Modulated Si doping as electron reservoir builds electric field and level tunnel coupling to reduce fine-structure splitting (FSS) and populate dominant XX and higher excitons XX + and XXX. Epoxy package thermal stress induces light hole (lh) with various behaviors related to the donor field: lh h 1 confined with more anisotropy shows an additional X Z line (its space to the traditional X lines reflects the field intensity) and larger FSS; lh h 2 delocalized to wetting layer shows a fast h 2 -h 1 decay; lh h 2 confined shows D 3h symmetric higher excitons with slow h 2 -h 1 decay and more confined h 1 to raise h 1 -h 1 Coulomb interaction.