  We report the routing of quantum light emitted by self-assembled InGaAs
quantum dots (QDs) into the optical modes of a GaAs ridge waveguide and its
efficient detection on-chip via evanescent coupling to NbN superconducting
nanowire single photon detectors (SNSPDs). Individual QD light sources embedded
within such integrated nano-photonic circuits are highly attractive for the
realization of quantum photonic circuits for many applications in photonic
information science. Here, we demonstrate that the waveguide coupled SNSPDs
primarily detect QD luminescence with scattered photons from the excitation
laser being negligible by comparison. The SNSPD detection efficiency from the
evanescently coupled waveguide modes is shown to be two orders of magnitude
higher when compared with operation under normal incidence illumination.
Furthermore, in-situ time resolved measurements show an average exciton
lifetime of 0.93 \pm 0.03 ns when recorded with the integrated detector with an
ultrafast timing jitter of only 72 \pm 2 ps showing the great potential of this
highly integrated quantum optics system.

Mesoscale and Nanoscale Physics;Superconductivity;Optics