Article
Optics
A. Gogyan, S. Guerin, Yu Malakyan
Summary: The study proposes an experimentally feasible protocol for deterministic generation of high-dimensional entanglement between distant multilevel atoms, achieved by triggering a two-photon wave packet with laser pulses. This allows for efficient transfer of atomic states between remote nodes and the construction of a three-dimensional quantum repeater.
Article
Engineering, Electrical & Electronic
Christian G. Bottenfield, Varghese A. Thomas, Stephen E. Ralph
Summary: Photonic frequency converters are optical systems used to translate data at RF or microwave frequencies to new carrier frequencies for processing or retransmission. The performance of these converters is governed by complex nonlinear functions that require detailed simulations to assess the impact of various architectures and components. This work provides analytic expressions for the primary metrics of photonic frequency converters, validated through comparison with simulations and experiment.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Yang Du, Dunke Lu, Qingping He, Xiaohui Fang
Summary: We propose a method to improve sensitivity by spatial-frequency doubling of the sensing signal in a single fiber interferometer. This method achieves the same effect as physically increasing the optical path difference (OPD) in an interferometer, but without increasing the size and introducing crosstalk and cost. Through the doubling of spatial frequencies, a Vernier effect with ultrahigh sensitivity is achieved in temperature sensing using a Sagnac interferometer.
IEEE SENSORS JOURNAL
(2023)
Article
Engineering, Electrical & Electronic
Jian Cui, Yuyang Gao, Shuailuo Huang, Jinyi Yu, Jiaxin Liu, Junchi Jia, Yongqi He, Zhangyuan Chen, Juhao Li
Summary: In this paper, a design method for degenerate-mode-selective couplers (DMSC) with side-polishing processing is proposed, and three kinds of DMSCs for different linearly-polarized (LP) modes (LP11, LP21, and LP31) in a weakly-coupled few-mode fiber (FMF) are designed. A pair of mode multiplexers/demultiplexers (MMUX/MDEMUX) consisting of cascaded mode-selective couplers (MSC) and DMSCs for all the 5 LP modes of the FMF are fabricated with side-polishing processing. The measurement results show that the MMUX and MDEMUX achieve low back-to-back insertion loss (IL) lower than 5.3 dB for all the 5 modes. Stable digital-signal-processing (DSP)-free 5-mode intensity modulation and direct detection (IM/DD) mode division multiplexing (MDM) transmission over a 10-km FMF is successfully demonstrated.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Chemistry, Analytical
Cailing Fu, Pengfei Li, Ronglong Sui, Zhenwei Peng, Huajian Zhong, Xiaoyu Yin, Yiping Wang
Summary: This research demonstrates a high-spatial-resolution OFDR distributed temperature sensor based on Au-SMF, which successfully demodulates the measured temperature between 50 and 600 degrees C with high accuracy and temperature sensitivity.
Article
Engineering, Electrical & Electronic
Xun Xie, Yundong Zhang
Summary: This paper presents an analytical approach to study the general type of step-index optical fiber modes and their variations. The results provide insights for developing new fibers and researching related fiber sensors.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Optics
Foued Amrani, Jonas H. Osorio, Frederic Delahaye, Fabio Giovanardi, Luca Vincetti, Benoit Debord, Frederic Gerome, Fetah Benabid
Summary: The design of hollow-core photonic crystal fibres with hybrid-lattice cladding significantly reduces confinement loss and preserves single-mode operation, showing potential for next-generation optical fibres.
LIGHT-SCIENCE & APPLICATIONS
(2021)
Article
Multidisciplinary Sciences
Cecilia Clivati, Alice Meda, Simone Donadello, Salvatore Virzi, Marco Genovese, Filippo Levi, Alberto Mura, Mirko Pittaluga, Zhiliang Yuan, Andrew J. Shields, Marco Lucamarini, Ivo Pietro Degiovanni, Davide Calonico
Summary: In this study, the authors use technologies from the optical clocks community to demonstrate a setup for twin-field quantum key distribution (QKD) that extends the coherence times by three orders of magnitude, overcoming the main challenge towards real-world implementation. They develop a solution using interferometry techniques to enable simultaneous key streaming and channel length control, and successfully demonstrate it on a 206 km field-deployed fiber. This technique represents an effective solution for real-world quantum communications.
NATURE COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Mark Pelusi, Ryosuke Matsumoto, Takashi Inoue, Shu Namiki
Summary: Improvements in the efficacy of optical phase conjugation (OPC) for compensating nonlinear signal distortion in long distance optical fiber links have been demonstrated. This is achieved by tailoring the link spans using step-parameter profiled fiber (SPF) to mitigate the impact of propagation loss on phase distortion before and after OPC. The addition of a dispersion element after OPC further enhances compensation in shorter subsections of spans. Numerical simulations and measurements show that the use of OPC and SPF designs significantly improve the Q(2)-factor and reduce bit error rate in different fiber link scenarios.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Nanjie Yu, Peter D. Dragic
Summary: The method based on Brillouin scattering is designed to evaluate the quantum conversion efficiency in Yb-doped optical fibers, providing insight into the origin of thermal energy in a fiber. The results show that the method is feasible and accurate, particularly useful for high-power fiber laser and amplifier applications, as well as a sensitive temperature probe in the study of anti-Stokes fluorescence cooling in optical fibers.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Physics, Multidisciplinary
Jikun Xie, Shengli Ma, Yalong Ren, Xinke Li, Shaoyan Gao, Fuli Li
Summary: We propose a novel scheme for coherent quantum transduction between microwave and optical signals based on a hybrid magnonic system. By utilizing a YIG sphere with optomechanical and optomagnetic properties to couple with a superconducting microwave resonator, we demonstrate the realization of nonreciprocal single-photon state conversion between microwave and optical modes through quantum interference effect.
NEW JOURNAL OF PHYSICS
(2023)
Article
Computer Science, Hardware & Architecture
He Li, Zihang Zhu, Congrui Gao, Guodong Wang, Tao Zhou, Xuan Li, Qingqing Meng, Yixiao Zhou, Shanghong Zhao
Summary: We propose a microwave photonic scheme for multi-functional radio over fiber communication links that achieves deep self-interference cancellation, long range transmission, and efficient signal recovery. By using double sideband modulation and the intermediate frequency signal amplitude regulation mechanism induced by fiber dispersion, we can satisfy the conditions for power fading compensation, amplitude matching, and phase reversion between self-interference and reference signals. The high precision delay matching in the optical domain ensures superior self-interference cancellation performance across a wide frequency range. Experimental analyses demonstrate high cancellation efficiency for single tone and broadband signals, as well as high quality signal transmission and recovery with different modulation formats and signal to interference ratios.
JOURNAL OF OPTICAL COMMUNICATIONS AND NETWORKING
(2023)
Article
Chemistry, Multidisciplinary
Shujing Li, Jiaxin Bao, Qiqi Deng, Lirong Chen, Hai Wang
Summary: We demonstrate a frequency conversion interface from rubidium D1 line (795 nm) to the optical communication L-band (1621 nm) to bridge atomic memory and fiber communication. By using two cascaded etalons and a low finesse Fabry-Perot cavity, we narrow the noise bandwidth to 11.7 MHz and show that the signal-noise ratio of the converted field is good enough.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Electrical & Electronic
Yang Du, Dunke Lu, Qingping He, Xiaohui Fang
Summary: By doubling the spatial frequency of the sensing signal and using a single fiber interferometer, the sensitivity of the sensor can be effectively improved without increasing its size, introducing additional crosstalk, or incurring additional costs.
IEEE SENSORS JOURNAL
(2023)
Article
Engineering, Electrical & Electronic
Florian Honz, Florian Prawits, Obada Alia, Hesham Sakr, Thomas Bradley, Cong Zhang, Radan Slavik, Francesco Poletti, George Kanellos, Reza Nejabati, Philip Walther, Dimitra Simeonidou, Hannes Huebel, Bernhard Schrenk
Summary: As quantum key distribution has matured, the integration with existing classical communication systems is crucial. The co-propagation of classical and quantum signals can be enhanced by novel hollow-core fibers, as shown in our demonstration. We achieved a secure key rate of 330 bit/s for a quantum channel at 1538 nm, while transmitting 25 x 10 Gb/s classical channels in the same hollow-core fiber link spanning over the C+L-band. Additionally, we successfully integrated the classical key-distillation channel onto this fiber link, making it bidirectional and reducing the need for multiple fibers. This is an important step towards deploying and integrating hollow-core fibers with DV-QKD for secure telecom networks of the future.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Physics, Applied
Yusuke Hisai, Yoshiki Nishida, Hiroshi Miyazawa, Takumi Kobayashi, Feng-Lei Hong, Daisuke Akamatsu
Summary: In this study, we achieved a second harmonic generation (SHG) of 116 mW at 461 nm in a periodically poled lithium niobate waveguide, when the power of the 922 nm fundamental light was coupled into the waveguide at 350 mW. The SHG system demonstrated good beam quality and is reliable for cold atom experiments, including research on optical lattice clocks.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Optics
Yuki Kojima, Kohei Ikeda, Yuto Tanabe, Daisuke Akamatsu, Feng-Lei Hong
Summary: This study introduces a new method for measuring the frequency of lasers in the short-wavelength region using an intermediate laser and noise-canceling scheme, successfully demonstrated on a GaN-based laser at 399nm.
Article
Physics, Applied
Raustin Reyes, Takaya Nakazato, Nobuaki Imaike, Kazuyasu Matsuda, Kazuya Tsurumoto, Yuhei Sekiguchi, Hideo Kosaka
Summary: The ability to manipulate and read out entanglement under a zero magnetic field using geometric phase has been demonstrated, which holds great significance for building fault-tolerant quantum computers and quantum repeater networks.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Multidisciplinary
Takaya Nakazato, Raustin Reyes, Nobuaki Imaike, Kazuyasu Matsuda, Kazuya Tsurumoto, Yuhei Sekiguchi, Hideo Kosaka
Summary: This study demonstrates a new method for quantum error correction under zero magnetic field, which can protect the nuclear spin of the nitrogen atom as a quantum memory. This approach eliminates the need for magnetic field manipulation and enables distributed quantum computation and a quantum internet.
COMMUNICATIONS PHYSICS
(2022)
Article
Physics, Applied
Takeshi Kondo, Seiho Shindo, Daisuke Yoshida, Yuma Goji, Mikitaka Nishihara, Taiki Aizawa, Feng-Lei Hong, Tomoyuki Horiki
Summary: A narrow-linewidth optical frequency comb is developed for frequency stabilization in order to couple telecommunication wavelength photons with quantum memories. Phase-locking to an iodine-stabilized Nd:YAG laser is used to achieve frequency stabilization in the developed optical frequency comb. The control laser of a Pr3+:Y2SiO5 (Pr:YSO) quantum memory is then phase-locked to the optical frequency comb, allowing for sufficient linewidth and frequency stability for multimode storage in the Pr:YSO quantum memory.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Optics
Kohei Ikeda, Takumi Kobayashi, Mayuko Yoshiki, Daisuke Akamatsu, Feng-Lei Hong
Summary: The hyperfine structures and absolute frequencies of iodine spectral lines were studied using specific laser and spectroscopy techniques. The results provide wavelength standards with reduced uncertainties for telecom applications.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2022)
Article
Optics
Yuhei Sekiguchi, Kazuki Matsushita, Yoshiki Kawasaki, Hideo Kosaka
Summary: This study demonstrates precise manipulation of an optically selected electron spin in a nitrogen-vacancy center in diamond through microwave-driven holonomic quantum gates. Optically addressable entanglement is achieved between the electron spin and an adjacent nitrogen nuclear spin. This research is significant for the development of large-scale quantum processors and memories.
Review
Physics, Applied
Hodaka Kurokawa, Moyuki Yamamoto, Yuhei Sekiguchi, Hideo Kosaka
Summary: This article proposes a scheme for quantum communication between superconducting qubits using a solid-state spin quantum memory as an interface, avoiding the issues of direct photon conversion and enabling entanglement distribution and parallel computation.
PHYSICAL REVIEW APPLIED
(2022)
Article
Nanoscience & Nanotechnology
Junia Nomura, Tomohiko Momma, Yuki Kojima, Yusuke Hisai, Takumi Kobayashi, Daisuke Akamatsu, Feng-Lei Hong
Summary: In this study, a compact and low-power experimental setup for cold atoms was demonstrated, which is essential for cold atom experiments such as optical clocks and quantum simulations. Yb atoms were directly loaded into a 3D magneto-optical trap (MOT) from a dispenser atomic source without using a Zeeman slower. The power consumption of the dispenser was approximately 3 W. Spectroscopy of the atomic beam from the dispenser showed a flux of 1.4 x 10(13) s(-1) cm(-2) on the Yb transition at 399 nm. Up to 4.1 x 10(7) atoms could be loaded into the MOT with specific laser powers.
Article
Physics, Applied
Ko Ito, Takeshi Kondo, Kyoko Mannami, Kazuya Niizeki, Daisuke Yoshida, Kohei Minaguchi, Mingyang Zheng, Xiuping Xie, Feng-Lei Hong, Tomoyuki Horikiri
Summary: The ability to transmit quantum states over long distances is crucial for the quantum internet, and quantum repeaters play a key role in achieving this. However, there is limited research on multiplexed photon sources and their coupling with multiplexed quantum memories. In this study, we demonstrate the storage of a frequency-multiplexed two-photon source in a quantum memory via wavelength conversion after a 10-km distribution. The developed system, which includes a frequency-stabilization system and a noise-reduction system, operates stably for more than 42 hours and can be applied to various physical systems requiring long-term system stability in quantum repeater systems.
PHYSICAL REVIEW APPLIED
(2023)
Article
Optics
Mayuko Yoshiki, Shogo Matsunaga, Kohei Ikeda, Daisuke Akamatsu, Feng-Lei Hong
Summary: This study measured the absolute frequencies and hyperfine structures of molecular iodine lines at 514 nm and obtained high-precision hyperfine constants. The results provide new optical frequency references for telecommunications and other applications.
EUROPEAN PHYSICAL JOURNAL D
(2023)
Article
Quantum Science & Technology
Akira Kamimaki, Keidai Wakamatsu, Kosuke Mikata, Yuhei Sekiguchi, Hideo Kosaka
Summary: This study demonstrates a method for deterministic and complete Bell state measurement using electron-nitrogen double qutrits at zero magnetic field. By using zero-field-split states as ancilla, the qubits of electron and nitrogen spins can be controlled holonomically, enabling the complete Bell state measurement without relying on any extra carbon isotopes.
NPJ QUANTUM INFORMATION
(2023)
Article
Optics
Mayuka Ichihara, Daisuke Yoshida, Feng-Lei Hong, Tomoyuki Horikiri
Summary: This study aims to improve the entanglement generation rate by frequency multiplexing the Bell-state measurements. Three frequency modes are mapped to a temporal mode by an atomic frequency comb, and Hong-Ou-Mandel interference is observed in each frequency mode. The visibility for all the modes was 40%-42%.
Article
Optics
Mayu Tanaka, Shota Suetomo, Nao Osato, Seiya Shinkawa, Feng-lei Hong, Daisuke Akamatsu
Summary: An experimental system for optically levitating nanoparticles in ultrahigh vacuum is demonstrated, which can be used for studying nanoparticles and building a mixed system with laser-cooled atoms.
Article
Optics
Daisuke Yoshida, Mayuka Ichihara, Takeshi Kondo, Feng-Lei Hong, Tomoyuki Horikiri
Summary: In this paper, a scheme is proposed to identify the frequency mode of spontaneously emitted photons with high resolution, even when the generation time is unknown. This is achieved by combining time-to-space and frequency-to-time mode mapping. The mapping of frequency mode to temporal mode using atomic frequency combs is also demonstrated for weak coherent pulses, with a frequency interval close to that of the atomic frequency comb quantum memory.
