arXiv subjects

Jin-Dong Wang

Publications and source records attributed to Jin-Dong Wang.

5 recordsLinked to original sources

arXiv2026

Phase coding semi-quantum key distribution system based on the Single-state protocol

Semi-quantum key distribution (SQKD) allows sharing random keys between a quantum user and a classical user, which significantly saves user resources, especially when using the Single-state protocol. However, the operation of the classical user, which involves measurement and resending using the Single-state protocol, presents technical difficulties in experiment and there is a security vulnerability of "tagged" attack in theory. To solve these problems, in our work, based on the Single-state protocol, we propose the "selective modulation" method and successfully implement a phase-encoded semi-quantum key distribution system. The system operates at a frequency of 100MHz and an average photon number of 0.1. The interference contrast achieved 97.45%, the average quantum bit error rate was 1.20%, and the raw key rate reached 88Kbps. Our experimental results demonstrate the feasibility and stability of the proposed phase-encoded SQKD system. Furthermore, we conducted an analysis of the "selective modulation" scheme in terms of quantum state evolution to assess the security of our system and ultimately proved that it can resist "tagged" attack. The classical user of our system requires only two optical devices and operates without relying on full quantum capabilities, thereby enhancing its application potential in quantum networks. This work validates the feasibility of SQKD experiments and provides ideas for future research on SQKD experiments and security studies.

quant-ph↗

arXiv2025

Long-distance high-precision and high-sensitivity time delay sensing based on fiber optic weak measurements

In fiber optic sensing, time delays induced by polarization mode dispersion can distort signals in systems relying on phase or intensity variations for measurement, degrading performance, especially in long distance, high-precision applications. To address this challenge, we propose a weak measurement-based scheme using intensity contrast ratio for high-precision, high-sensitivity fiber optic delay estimation under large inherent time delays. We demonstrate that a narrower light source bandwidth enhances the effective sensing distance for high-sensitivity measurements. Our results show that, even with large inherent time delays, the measurement precision and sensitivity remain comparable to those of biased weak measurement, enabling detection of time delay variations at the attosecond level, corresponding to a 25.5 Pa water pressure change. The scheme is also robust against fiber misalignment errors, offering a novel solution for long-distance distributed fiber-optic sensing and broadening the applications of weak measurement techniques.

physics.optics↗

arXiv2022

Telecom-band Multi-Type Spontaneous Parametric Downconversion in Periodically Polarized Nonlinear Materials

Spontaneous parametric downconversion is an essential technique in quantum optics experiments. In this paper, various quasi-phase-matching processes in several typical periodically polarized nonlinear materials are analyzed and calculated. Furthermore, a general method for realizing multiple types of quasi-phase-matching in a monolithic material is presented. Finally, a novel design to prepare multiple entangled photon pairs based on the Sagnac interferometer is discussed. This technology can be applied to tiny optical paths in the telecom C band, saving both cost and space.

quant-ph↗

arXiv2021

Schrödinger's cat state of optical parallel universes

Parallel worlds are imaginative ideas in quantum mechanics and cosmology. The superpositions of parallel worlds are novel states of quantum gravity and have no classical correspondences generally. In this letter, we investigate the superposition or the Schrödinger's cat state of optical parallel worlds, which could be realized in laboratory and may shed some light on the detection of parallel universes in a real world. We propose two realizable experimental schemes, which enable to explore the mysterious `parallel universes' by a Mach-Zehnder interferometer. The first one is based on an atomic ensemble in a superposition state, which is a fat Schrödinger's cat state. The second one is to prepare a photon in a superposition of different paths, where each path lies in an optical parallel universe.

quant-ph↗

arXiv2020

Tunable Optomechanically Induced Sideband Comb

Cavity optomechanical system can exhibit higher-order sideband comb effect when it is driven by a control field $ω_{c}$ and a probe field $ω_{p}$, and works in the non-perturbative regime, as was shown in a previous work [Xiong et al., Opt. Lett. 38, 353 (2013)]. The repetition frequency of such a comb is equal to the mechanical frequency $ω_{b}$ and is untunable, which limits the precision of the comb. Here we address this problem by driving the system with an additional strong probe field $ω_{f}$, and the detuning between $ω_{f}$ and $ω_{c}$ is equal to $ω_{b}/n$ (here $n$ is an integer), i.e., this detuning is a fraction of the mechanical frequency. In this case, we obtain some interesting results. We find that not only the integer-order (higher-order) sidebands, but also the fraction-order sidebands, and the sum and difference sidebands between the integer- and fraction-order sidebands, will appear in the output spectrum. The generated nonlinear sidebands constitute an optomechanically induced sideband comb (OMISC). The frequency range and the repetition frequency of the OMISC are proportional to the sideband cutoff-order number and the sideband interval, respectively. We show that we can extend the frequency range of the OMISC by increasing the intensity of the probe field $ω_{p}$. More importantly, we can decrease the repetition frequency, and consequently, improve the precision of the OMISC by increasing $n$ and the intensity of the probe field $ω_{f}$.

quant-ph↗