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Quantum Computing, Communication, and Simulation

Side-channel-free quantum key distribution source using a KTP polarization modulator and a broadband laser

Tahereh Rezaei, Andrew Conrad, Philip R. Battle, Daniel J. Gauthier, Paul G. Kwiat

Published Jan 24, 2023• 0 citations
Publisher

Abstract

We present progress on demonstrating a side-channel-free, decoy-state quantum key distribution (QKD) source based on a polarization-modulator and a wavelength-stable attenuated pulsed laser. By modulating the polarization of the quantum state, a three-state QKD protocol is achieved. The polarization-modulator-based QKD source improves security by removing several sources of side-channel attacks that exist when multiple sources are used to generate different QKD states. Here we present our single-source design, as well as an evaluation of critical subsystems characterized by the quantum bit error rate (QBER), quantum state tomography, and achievable key rates. The QKD source is intended to operate using minimal size, weight, and power (SWaP). In our system, we use a custom KTP waveguide modulator designed and fabricated by AdvR. Our QKD source can be operated using both narrow-band and broadband lasers, and we present characterization data using a He-Ne laser, and a diode laser, respectively. The polarization-modulator-based QKD source has applications in future mobile quantum networks incorporating unmanned aerial vehicles (UAV) and autonomous vehicles, as well as fiber-based quantum networks.

DOI
10.1117/12.2648018

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We present progress on demonstrating a side-channel-free, decoy-state quantum key distribution (QKD) source based on a polarization-modulator and a wavelength-stable attenuated pulsed laser. By modulating the polarization of the quantum state, a three-state QKD protocol is achieved. The polarization-modulator-based QKD source improves security by removing several sources of side-channel attacks that exist when multiple sources are used to generate different QKD states. Here we present our single-source design, as well as an evaluation of critical subsystems characterized by the quantum bit error rate (QBER), quantum state tomography, and achievable key rates. The QKD source is intended to operate using minimal size, weight, and power (SWaP). In our system, we use a custom KTP waveguide modulator designed and fabricated by AdvR. Our QKD source can be operated using both narrow-band and broadband lasers, and we present characterization data using a He-Ne laser, and a diode laser, respectively. The polarization-modulator-based QKD source has applications in future mobile quantum networks incorporating unmanned aerial vehicles (UAV) and autonomous vehicles, as well as fiber-based quantum networks.
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Measurement-device-independent quantum key distribution (MDI-QKD) can be immune to all detector side-channel attacks and guarantee the information-theoretical security even with uncharacterized single photon detectors. MDI-QKD has been demonstrated in both laboratories and field-tests by using attenuated lasers combined with the decoy-state technique. However, it is a critical assumption that the sources used by legitimate participants are trusted in MDI-QKD. Hence, it is possible that a potential security risk exists. Here we propose a new scheme of polarization-encoding-based MDI-QKD with a single untrusted source, by which the complexity of the synchronization system can be reduced and the success rate of the Bell-state measurement can be improved. Meanwhile, the decoy-state method is employed to avoid the security issues introduced by a non-ideal single photon source. We also derive a security analysis of the proposed system. In addition, it seems to be a promising candidate for the implementation for QKD network in the near future.