Today’s society heavily relies on secure communications, which can be guaranteed by Quantum Key Distribution (QKD), the most mature quantum technology. However, achieving long-distance links without relying on trusted nodes is still challenging. An important limitation is the non-ideality of detection systems, where intrinsic dark counts can hinder key extraction. This work proposes using state-of-the-art superconducting nanowire singlephoton detectors (SNSPD) with ultra-low dark count rates (<1 Hz) to reduce the quantum bit error rate (QBER) and achieve a higher secret key rate. Together with a high-rate QKD transmitter and a self-stabilizing receiver, we enabled a key exchange over 55 dB, corresponding to 340 km over an ultra-low-loss optical fiber.
Superconducting Microstrips Single Photon Detectors (SMSPDs) are currently of crucial interest in numerous applications thanks to their excellent performance in terms of high detection efficiency, short jitter time, and low dark count rate, meeting the necessities of covering a large active area using low-cost technology. In this scenario, the research of new materials to detect from telecom (1550 nm) to mid-infrared wavelengths plays an important role. In this work we fabricated SMSPDs made of NbRe, an innovative material recently proposed in this field. We realized devices with different microstrip configurations based on single microstrips and pairs of parallel microstrips to investigate the role of the geometry. Single photon detection sensitivity at 1550 nm wavelength at a temperature of 1.79 K was demonstrated. The results obtained are encouraging for the photon detection with NbRe-based devices covering large areas.
A photon number resolving detector (PNRD) is a device providing a different output depending on the number of incident photons in the single or few photons regime. This tool is crucial in several applications such as quantum communication, boson sampling, photon sources characterization and so on. PNRD are not new players in ultraviolet or visible wavelengths, but superconducting nanostrips provide a performing counterpart also in the near-infrared, where the aforementioned applications would like to operate. In this work we present a comprehensive description of the operation of an eight-pixel PNRD at the telecom wavelength of 1550 nm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.