Freiburg 2024 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 13: Quantum Technologies

Q 13.1: Talk

Monday, March 11, 2024, 17:00–17:15, HS 3219

Alternative approach to quantum pulse gates — •Ankita Khanda, Laura Serino, Michael Stefszky, Benjamin Brecht, and Christine Silberhorn — Integrated Quantum Optics, Institute for Photonic Quantum Systems, Paderborn Univerisity, Warburger Str. 100, 33098 Paderborn, Germany

Deep space communications and time-of-flight LiDAR applications can utilize ultrashort optical pulses for high bit rate and precision; however, successful implementation of such systems is challenging and requires single- or few-photon detection with very low mean photon numbers and high SNR. Noise rejection is critical in free-space, where background light is present or detected photon count is low. The most efficient method of noise elimination in the spectral-temporal domain is coherent time-frequency filtering. A quantum pulse gate (QPG) is a highly selective coherent temporal mode (TM) filter based on sum-frequency generation in a periodically-poled lithium niobate (PPLN) waveguide capable of single-photon level operation at telecom wavelengths without additional noise. In this work, we investigate noise effects of frequency up-conversion in target TM detection at telecom-only wavelengths in a PPLN QPG down to single-photon level. The pump and signal photon location in the telecom-range with small spectral separation allows for easy integration into the standard fiber-optic networks, but may give rise to additional noise channels. We will report progress on the project, including first results.

Keywords: Coherent filtering; Frequency conversion; Lithium niobate waveguide; Integrated quantum optics