Abstract
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.
Highlights
Quantum communication and information processing (QCIP)[1, 2] currently evolve from fundamental research towards real life applications
The spectrum of the uncoated waveguide shows a main peak with a bandwidth (FWHM) of 0.4 nm (≈ 157 GHz), as predicted for the interaction length
The resolution of the spectrometer (≈ 0.15 nm) is too coarse to reveal details of the spectra, one can already derive that the pair generation occurs within clusters with a cluster separation of about 0.24 nm (≈ 90 GHz). This separation is determined by the beating of the free spectral ranges (FSRs) of signal and idler, which theoretically are FSRs ∼ 5.2 GHz and FSRi ∼ 5.5 GHz
Summary
Quantum communication and information processing (QCIP)[1, 2] currently evolve from fundamental research towards real life applications. Quantum repeater architectures have been proposed [4, 11, 12] to overcome current limitations of long distance quantum communication due to transmission losses These typically require spectrally narrowband two-color photon pairs for instance to address the absorption line of the storage medium in a quantum memory (QM) [13, 14, 15, 16, 17, 18] with one photon and transmit the second over a fiber network. Such QMs usually have their absorption in the visible or near infrared, i.e. far away from the telecommunication range. Among the most promising materials for highbandwidth QM’s are solid-state atomic ensembles, rare-earth ion doped crystals or glasses [19, 20, 21, 22] and QM at room-temperature [23, 24]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
