We demonstrate a spectrally broadband and effcient technique for collecting photoluminescence from a single InAs quantum dot directly into a standard single mode optical fiber. In this approach, an optical fiber taper waveguide is placed in contact w
ith a suspended GaAs nanophotonic waveguide with embedded quantum dots, forming an effcient and broadband directional coupler with standard optical fiber input and output. Effcient photoluminescence collection over a wavelength range of tens of nanometers is demonstrated, and a maximum collection effciency of 6.05 % (corresponding single photon rate of 3.0 MHz) into a single mode optical fiber was estimated for a single quantum dot exciton.
We demonstrate a nanostructure composed of partially etched annular trenches in a suspended GaAs membrane, designed for efficient and moderately broadband (approx. 5 nm) emission extraction from single InAs quantum dots. Simulations indicate that a d
ipole embedded in the nanostructure center radiates upwards into free space with a nearly Gaussian far-field, allowing a collection efficiency > 80 % with a high numerical aperture (NA=0.7) optic, and with 12X Purcell radiative rate enhancement. Fabricated devices exhibit an approx. 10 % photon collection efficiency with a NA=0.42 objective, a 20X improvement over quantum dots in unpatterned GaAs. A fourfold exciton lifetime reduction indicates moderate Purcell enhancement.
