arXiv subjects

Vadim Rodimin

Publications and source records attributed to Vadim Rodimin.

5 recordsLinked to original sources

arXiv2026

Broadband Characterization of Polarization Mode Dispersion for Quantum Communication Channels

We present a method for characterizing polarization fiber channels carrying broadband quantum signals, where narrowband filtering would waste photon flux. Wavelength-dependent polarization mode dispersion (PMD) maps each input state to a trajectory on the Poincar\'e sphere; we show that the singular value decomposition of the band-averaged rotation matrix yields, in closed form, the optimal input states, the mutually unbiased measurement bases, and their infidelities. The three singular values provide a compact, bandwidth-dependent channel signature that separates first- from higher-order PMD, and the resulting 5%-infidelity bandwidth gives a practical filtering budget. We characterize deployed fiber links in Masdar City and demonstrate PMD mitigation by concatenating two channels through a single polarization controller.

quant-ph↗

arXiv2025

Cross-correlation scheme for quantum optical coherence tomography based on Michelson interferometer

Quantum optical coherence tomography (QOCT) offers a simple way to cancel dispersion broadening in a sample while also providing twice the resolution compared to classical OCT. However, to achieve these advantages, a bright and broadband source of entangled photon pairs is required. A simple implementation uses collinear spontaneous parametric down-conversion in a Michelson interferometer (MI), yet this autocorrelation scheme suffers from parasitic terms and sensitivity to phase noise. Here, we introduce a cross-correlation MI-based QOCT that overcomes these drawbacks, significantly advancing QOCT toward practical applications.

quant-ph↗

arXiv2024

Impact of polarization mode dispersion on entangled photon distribution

Polarization mode dispersion (PMD) in optical fibers poses a major challenge for maintaining the fidelity of quantum states for quantum communications. In this work, a comprehensive model linking the probability of quantum measurement errors (infidelity) to PMD is developed and validated by experimental measurements of differential group delay and quantum bit error rate (QBER). Our research proposes effective methods to mitigate PMD effects for broadband entangled photons and evaluates the impact of higher-order PMD effects. The model provides an experimentally verified framework for the optimization of commercial quantum key distribution systems in deployed fiber optic lines.

quant-ph↗

arXiv2021

Optimizing the deployment of quantum key distribution switch-based networks

Quantum key distribution (QKD) networks provide an infrastructure for establishing information-theoretic secure keys between legitimate parties via quantum and authentic classical channels. The deployment of QKD networks in real-world conditions faces several challenges, which are related in particular to the high costs of QKD devices and the condition to provide reasonable secret key rates. In this work, we present a QKD network architecture that provides a significant reduction in the cost of deploying QKD networks by using optical switches and reducing the number of QKD receiver devices, which use single-photon detectors. We describe the corresponding modification of the QKD network protocol. We also provide estimations for a network link of a total of 670 km length consisting of 8 nodes, and demonstrate that the switch-based architecture allows achieving significant resource savings of up to 28%, while the throughput is reduced by 8% only.

quant-ph↗

arXiv2021

Go-and-return phase encoded SR QKD and its security consideration

In this work, we study the security of coherent-state quantum key distribution with a strong reference pulse. The consideration is based on a powerful soft filtering attack and uses realistic parameters of the equipment. Our model allows us to relate the secure key generation rate and distance with the energy of signal and reference pulses. We propose a two-pass quantum key distribution phase encoding optical scheme with a strong reference pulse. This simple for realization scheme is experimentally tested showing stable operation. Here we describe the tuning technique and solution for the problem of weak signal pulse shadowing by a bright reference pulse with the relative intensity difference of more than 60\,dB between them.

quant-ph↗