Single photon frequency up-conversion and its applications

Eiichi Kuramochi, Masaya Notomi

Lijun Ma, Oliver Slattery, Xiao Hong Tang

We have studied single photon level frequency up-conversion, and developed efficient single photon detectors and a highly sensitive spectrometer at a telecommunication wavelength (around 1310 nm). We have applied the detector and spectrometer to the implementation of a quantum key distribution system; to the characterization of an entangled photon source and a single photon source from quantum dots; to increase the temporal resolution of the single photon detector; and to study on high-order temporal correlation following frequency conversion. In this paper, we will present an overview on the frequency up-conversion technique and its applications in quantum information systems.

Paulina S. Kuo, Jason S. Pelc, Oliver Slattery +3 more

We demonstrate low-noise and efficient frequency conversion by sum-frequency mixing in a periodically poled LiNbO(3) (PPLN) waveguide. Using a 1556 nm pump, 1302 nm photons are efficiently converted to 709 nm photons. We obtain 70% conversion efficiency in the PPLN waveguide and >50% external conversion efficiency with 600 noise counts per second at peak conversion with continuous-wave pumping. We simultaneously achieve low noise and high conversion efficiency by careful spectral filtering. We discuss the impact of low-noise frequency translation on single-photon upconversion detection and quantum information applications.

John Rarity, Stephen C. Kitson, Paul R. Tapster

Paulina S. Kuo, Jason S. Pelc, Oliver Slattery +3 more

Tong Xiang, Qi-Chao Sun, Yuanhua Li +2 more

Frequency conversion of single photons is an important technology for quantum interface and quantum communication networks. Here, single-photon frequency conversion in the telecommunication band is experimentally demonstrated via cascaded quadratic nonlinear processes. Using cascaded quasi-phase-matched sum and difference frequency generation in a periodically poled lithium niobate waveguide, the signal photon of a photon pair from spontaneous down-conversion is precisely shifted to identically match its counterpart, i.e., the idler photon, in frequency to manifest a clear nonclassical dip in the Hong-Ou-Mandel interference. Moreover, quantum entanglement between the photon pair is maintained after the frequency conversion, as is proved in time-energy entanglement measurement. The scheme is used to switch single photons between dense wavelength-division multiplexing channels, which holds great promise in applications in realistic quantum networks.