2015/04/08 by Kai-Hong Luo, Harald Herrmann, Stephan Krapick +8 · 1 citation
Engineering · Physics and Astronomy · #Advanced Fiber Laser Technologies #Bandwidth (computing) #Computer science #Lithium niobate #Narrowband #Optical fiber #Optics #Optoelectronics #Photon #Photonic and Optical Devices #Physics #Quantum #Quantum entanglement #Quantum optics and atomic interactions #Single-mode optical fiber #Single-photon source #Spontaneous parametric down-conversion #Telecommunications #Waveguide #physics.optics #quant-ph
paper · pdf · doi:10.1088/1367-2630/17/7/073039
arxiv created 2015/04/08 · openalex publication_date 2015/08/03 · arxiv updated 2015/09/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
The practical prospect of quantum communication and information processing relies on sophisticated single-photon pairs, which feature a controllable waveform, narrow spectrum, excellent purity, fiber compatibility, and miniaturized design. For practical realizations, stable, miniaturized, low-cost devices are required. Sources with one or some of the above characteristics have already been demonstrated, but it is quite challenging to obtain a source with all of the described characteristics simultaneously. Here we report on an integrated single-longitudinal-mode, non-degenerate, narrowband photon pair source that exhibits all the requirements needed for quantum applications. The device is composed of a periodically poled, Ti-indiffused, lithium niobate waveguide with high reflective dielectric mirror coatings deposited on the waveguide end-faces. Photon pairs with wavelengths around 890 and 1320 nm are generated via type II phase-matched parametric down-conversion (PDC). Clustering in this dispersive cavity restricts the whole conversion spectrum to one single-longitudinal mode in a single cluster, yielding a narrow bandwidth of only 60 MHz. The high conversion efficiency in the waveguide, together with the spectral clustering in the doubly resonant waveguide, leads to a high brightness of pairs/(s mW MHz). This source exhibits prominent single-longitudinal-mode purity and remarkable temporal shaping capability. In particular, due to temporal broadening, we can observe that the coherence time of the two-photon component of the PDC state is actually longer than that of the single-photon states. The miniaturized monolithic design enables this source to have various fiber communication applications.