Integrated photonic quantum technologies with fiber-integrated single photon emitters

Miniaturization of quantum optical devices down to mu m-dimensions and integration into fibre optical networks is a major prerequisite for future implementations of quantum information communication and processing applications. Also scalability, long-term stability and room-temperature operation are important properties of such devices. Lately there have been major improvements in down-sizing logical structures and functionalizing optical fibers. Here we present an alignment free, mu m-scale single photon source consisting of a single quantum emitter on an optical fiber operating at room temperature. It easily integrates into fiber optic networks for quantum cryptography or quantum metrology applications.(1) Near-field coupling of a single nitrogen-vacancy center is achieved in a bottom-up approach by placing a pre-selected nanodiamond directly on the fiber facet. Its high photon collection efficiency is equivalent to a far-field collection via an objective with a numerical aperture of 0.82. Furthermore, simultaneous excitation and recollection through the fiber is possible introducing a fiber-connected single emitter sensor that allows near-field probing with quantum mechanical properties.