Philippe Grangier | LIP6 - Équipe QI

Experimental demonstration of Continuous-Variable Quantum Key Distribution with a silicon photonics integrated receiver

Wed, 25 Dec 2024 00:00:00 +0000

Quantum Key Distribution (QKD) is a prominent application in the field of quantum cryptography providing information-theoretic security for secret key exchange. The implementation of QKD systems on photonic integrated circuits (PICs) can reduce the size and cost of such systems and facilitate their deployment in practical infrastructures. To this end, continuous-variable (CV) QKD systems are particularly well-suited as they do not require single-photon detectors, whose integration is presently challenging. Here we present a CV-QKD receiver based on a silicon PIC capable of performing balanced detection. We characterize its performance in a laboratory QKD setup using a frequency multiplexed pilot scheme with specifically designed data processing allowing for high modulation and secret key rates. The obtained excess noise values are compatible with asymptotic secret key rates of 2.4 Mbit/s and 220 kbit/s at an emulated distance of 10 km and 23 km, respectively. These results demonstrate the potential of this technology towards fully integrated devices suitable for high-speed, metropolitan-distance secure communication.

QOSST : A Highly Modular Open Source Software for Continuous-Variable Quantum Key Distribution

Wed, 13 Nov 2024 00:00:00 +0000

Shaped Constellation Continuous Variable Quantum Key Distribution: Concepts, Methods and Experimental Validation

Thu, 01 Aug 2024 00:00:00 +0000

Quantum key distribution (QKD) enables the establishment of secret keys between users connected via a channel vulnerable to eavesdropping, with information-theoretic security, that is, independently of the power of a malevolent party (Scarani et al., 2009). QKD systems based on the encoding of the key information on continuous variables (CV), such as the values of the quadrature components of coherent states (Weedbrook et al., 2012), (Diamanti and Leverrier, 2015), present the major advantage that they only require standard telecommunication technology. However, the most general security proofs for CV-QKD required until now the use of Gaussian modulation by the transmitter, complicating practical implementations (Jouguet et al., 2013), (Zhang et al., 2020), (Jain et al., 2022). Here, we experimentally implement a protocol that allows for arbitrary, Gaussian-like, discrete modulations, whose security is based on a theoretical proof that applies generally to such situations (Denys et al., 2021). These modulation formats are compatible with the use of powerful tools of coherent optical telecommunication, allowing our system to reach an estimated performance of tens of megabit per second secret key rates over 25 km.

QOSST: A Highly Modular Open Source Platform for Continuous Variable Quantum Key Distribution Applications

Sun, 23 Jun 2024 00:00:00 +0000

We present a highly modular Open Source Software to perform CV-QKD experiments. The software is hardware agnostic and was benchmarked on bulk and integrated receivers, reaching state of the art secret key rates.

QOSST: A Highly-Modular Open Source Platform for Experimental Continuous-Variable Quantum Key Distribution

Mon, 29 Apr 2024 00:00:00 +0000

Quantum Key Distribution (QKD) enables secret key exchange between two remote parties with information-theoretic security rooted in the laws of quantum physics. Encoding key information in continuous variables (CV), such as the values of quadrature components of coherent states of light, brings implementations much closer to standard optical communication systems, but this comes at the price of significant complexity in the digital signal processing techniques required for operation at low signal-to-noise ratios. In this work, we wish to lower the barriers to entry for CV-QKD experiments associated to this difficulty by providing a highly modular, open source software that is in principle hardware agnostic and can be used in multiple configurations. We benchmarked this software, called QOSST, using an experimental setup with a locally generated local oscillator, frequency multiplexed pilots and RF-heterodyne detection, and obtained state-of-the-art secret key rates of the order of Mbit/s over metropolitan distances at the asymptotic limit. We hope that QOSST can be used to stimulate further experimental advances in CV-QKD and be improved and extended by the community to achieve high performance in a wide variety of configurations.

Experimental Demonstration of Continuous-Variable Quantum Key Distribution with a Photonic Integrated Receiver and Modular Software

Wed, 22 Nov 2023 00:00:00 +0000

High-speed continuous-variable quantum key distribution with advanced digital signal processing

Sun, 02 Jul 2023 00:00:00 +0000

Continuous-variable quantum key distribution (CV-QKD) is a promising solution for providing high secure key rates in moderate loss channels. A great advantage with respect to discrete-variable (DV) systems is the use of a technology similar to the one used in classical coherent communication, in particular for the detection system, which can operate at room temperature and benefits from an easier integration process. In addition to this, the use of advanced digital signal processing (DSP) techniques developed for classical communication allows for bandwidth-efficient temporal shaping, which optimizes the performance of the CV-QKD system. These techniques applied to the detected signal are also fundamental for using a locally generated local oscillator, correcting frequency and phase differences using frequency-multiplexed pilots generated by the transmitter. In this presentation, we will describe how these DSP techniques can be applied to a CV-QKD system and show some recent experimental results obtained by our research group, including results for a receiver based on a Photonic Integrated Circuit (PIC).

Dispositifs électroniques avancés pour la CV-QKD

Mon, 12 Jun 2023 00:00:00 +0000

CV-QKD Receiver Platform Based On A Silicon Photonic Integrated Circuit

Sun, 05 Mar 2023 00:00:00 +0000

We report on the characterization of a SiGe PIC-based receiver along with its usage in a Gaussian-modulated coherent state CV-QKD setup. Excess noise measurements lead to secret key rate estimations of 280 kbit/s at 6.9 km.

CV-QKD Receiver Platform Based On A Silicon Photonic Chip

Wed, 16 Nov 2022 00:00:00 +0000

A Versatile PIC-based CV-QKD receiver

Wed, 05 Oct 2022 00:00:00 +0000

Long-range QKD without trusted nodes is not possible with current technology

Fri, 09 Sep 2022 00:00:00 +0000

A Versatile PIC-based CV-QKD Receiver

Mon, 29 Aug 2022 00:00:00 +0000

Experimental Demonstration of Discrete Modulation Formats for Continuous Variable Quantum Key Distribution

Sun, 24 Jul 2022 00:00:00 +0000

A Versatile CV-QKD system with a PIC-based receiver

Mon, 11 Jul 2022 00:00:00 +0000

A versatile and high-performance PIC-based CV-QKD receiver

Wed, 03 Nov 2021 00:00:00 +0000

High-Rate Continuous Variable Quantum Key Distribution Based on Probabilistically Shaped 64 and 256-QAM

Mon, 13 Sep 2021 00:00:00 +0000

We designed a CV-QKD system with off-the-shelf components and established the feasibility of distributing 67.6 and 66.8 Mb/s secret key rates on average over a 9.5 km SMF link, using respectively probabilistically shaped 64 and 256 QAM, and relying on a novel analytical security proof.

Demonstration of Probabilistic Constellation Shaping for Continuous Variable Quantum Key Distribution

Sun, 06 Jun 2021 00:00:00 +0000

We demonstrate, for the first time to our knowledge, continuous-variable quantum key distribution using probabilistically-shaped 1024-QAM and true local oscillator, achieving 38.3Mb/s secret key rate over 9.5km, averaged over the transmission time of 100 blocks.

Asymptotic security of continuous-variable quantum key distribution with a discrete modulation

Tue, 25 Jun 2019 00:00:00 +0000

We establish a lower bound on the asymptotic secret key rate of continuous-variable quantum key distribution with a discrete modulation of coherent states. The bound is valid against collective attacks and is obtained by formulating the problem as a semidefinite program. We illustrate our general approach with the quadrature-phase-shift-keying modulation scheme and show that distances over 100 km are achievable for realistic values of noise. We also discuss the application to more complex quadrature-amplitude-modulation schemes. This result opens the way to establishing the full security of continuous-variable protocols with a discrete modulation, and thereby to the large-scale deployment of these protocols for quantum key distribution.