1
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Rübeling P, Heine J, Johanning R, Kues M. Quantum and coherent signal transmission on a single-frequency channel via the electro-optic serrodyne technique. SCIENCE ADVANCES 2024; 10:eadn8907. [PMID: 39058776 PMCID: PMC11277375 DOI: 10.1126/sciadv.adn8907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 06/21/2024] [Indexed: 07/28/2024]
Abstract
Fiber-optical networks are well established to accommodate global data traffic via coherent information transmission. The next generation of telecommunications will require the integration of quantum information into fiber-optic networks, e.g., for quantum key distribution. A promising and scalable route to enable quantum networking is encoding quantum information into the frequency of photons. While the cointegration of frequency-entangled photons with coherent information transmission is achieved via spectral multiplexing, more resource-efficient approaches are required. In this work, we introduce and experimentally demonstrate a transceiver concept that enables the transmission of coherent and frequency-entangled photons over a single-frequency channel. Our concept leverages the serrodyne technique via electro-optic phase modulation leading to very different dynamics for entangled and coherent photons. This enables temporal multiplexing of the respective signals. We demonstrate the preservation of entanglement over the channel in the presence of coherent light. Our approach reveals a strong potential for efficient bandwidth use in hybrid networks.
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Affiliation(s)
- Philip Rübeling
- Institute of Photonics (IOP), Leibniz University Hannover, Nienburger Straße 17, 30167 Hannover, Germany
| | - Jan Heine
- Institute of Photonics (IOP), Leibniz University Hannover, Nienburger Straße 17, 30167 Hannover, Germany
| | - Robert Johanning
- Institute of Photonics (IOP), Leibniz University Hannover, Nienburger Straße 17, 30167 Hannover, Germany
- Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering - Innovation Across Disciplines), Leibniz University Hannover, Welfengarten 1, 30167 Hannover, Germany
| | - Michael Kues
- Institute of Photonics (IOP), Leibniz University Hannover, Nienburger Straße 17, 30167 Hannover, Germany
- Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering - Innovation Across Disciplines), Leibniz University Hannover, Welfengarten 1, 30167 Hannover, Germany
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2
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Ding Y, Wei Z, Wang Y, Yang C, Bao C. Theoretical Analysis of Microcavity Simultons Reinforced by χ^{(2)} and χ^{(3)} Nonlinearities. PHYSICAL REVIEW LETTERS 2024; 132:013801. [PMID: 38242661 DOI: 10.1103/physrevlett.132.013801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 11/27/2023] [Indexed: 01/21/2024]
Abstract
High-Q microcavities with quadratic and cubic nonlinearities add lots of versatility in controlling microcombs. Here, we study microcavity simulton and soliton dynamics reinforced by both χ^{(2)} and χ^{(3)} nonlinearities in a continuously pumped microcavity. Theoretical analysis based on the Lagrangian approach reveals the soliton peak power and gain-loss balance are impacted by the flat part of the intracavity pump, while the dark-pulse part of the pump leads to a nearly constant soliton group velocity change. We also derived a soliton conversion efficiency upper limit that is fully determined by the coupling condition and the quantum-limited soliton timing jitter in the χ^{(2,3)} system. Numerical simulations confirm the analytical results. Our theory is particularly useful for investigating AlN microcombs and sheds light on the interplay between χ^{(2)} and χ^{(3)} nonlinearities within microcavity simultons.
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Affiliation(s)
- Yulei Ding
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, China
| | - Ziqi Wei
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, China
| | - Yifei Wang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, China
| | - Changxi Yang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, China
| | - Chengying Bao
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, China
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3
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Chapman JC, Miloshevsky A, Lu HH, Rao N, Alshowkan M, Peters NA. Two-mode squeezing over deployed fiber coexisting with conventional communications. OPTICS EXPRESS 2023; 31:26254-26275. [PMID: 37710490 DOI: 10.1364/oe.492539] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 07/13/2023] [Indexed: 09/16/2023]
Abstract
Squeezed light is a crucial resource for continuous-variable (CV) quantum information science. Distributed multi-mode squeezing is critical for enabling CV quantum networks and distributed quantum sensing. To date, multi-mode squeezing measured by homodyne detection has been limited to single-room experiments without coexisting classical signals, i.e., on "dark" fiber. Here, after distribution through separate fiber spools (5 km), -0.9 ± 0.1-dB coexistent two-mode squeezing is measured. Moreover, after distribution through separate deployed campus fibers (about 250 m and 1.2 km), -0.5 ± 0.1-dB coexistent two-mode squeezing is measured. Prior to distribution, the squeezed modes are each frequency multiplexed with several classical signals-including the local oscillator and conventional network signals-demonstrating that the squeezed modes do not need dedicated dark fiber. After distribution, joint two-mode squeezing is measured and recorded for post-processing using triggered homodyne detection in separate locations. This demonstration enables future applications in quantum networks and quantum sensing that rely on distributed multi-mode squeezing.
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4
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Kaushal S, Aadhi A, Roberge A, Morandotti R, Kashyap R, Azaña J. All-fibre phase filters with 1-GHz resolution for high-speed passive optical logic processing. Nat Commun 2023; 14:1808. [PMID: 37002203 PMCID: PMC10066316 DOI: 10.1038/s41467-023-37472-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 03/10/2023] [Indexed: 04/03/2023] Open
Abstract
Photonic-based implementation of advanced computing tasks is a potential alternative to mitigate the bandwidth limitations of electronics. Despite the inherent advantage of a large bandwidth, photonic systems are generally bulky and power-hungry. In this respect, all-pass spectral phase filters enable simultaneous ultrahigh speed operation and minimal power consumption for a wide range of signal processing functionalities. Yet, phase filters offering GHz to sub-GHz frequency resolution in practical, integrated platforms have remained elusive. We report a fibre Bragg grating-based phase filter with a record frequency resolution of 1 GHz, at least 10× improvement compared to a conventional optical waveshaper. The all-fibre phase filter is employed to experimentally realize high-speed fully passive NOT and XNOR logic operations. We demonstrate inversion of a 45-Gbps 127-bit random sequence with an energy consumption of ~34 fJ/bit, and XNOR logic at a bit rate of 10.25 Gbps consuming ~425 fJ/bit. The scalable implementation of phase filters provides a promising path towards widespread deployment of compact, low-energy-consuming signal processors.
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Affiliation(s)
- Saket Kaushal
- Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Lionel-Boulet Blvd., Varennes, J3X 1P7, Quebec, Canada
| | - A Aadhi
- Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Lionel-Boulet Blvd., Varennes, J3X 1P7, Quebec, Canada
| | - Anthony Roberge
- Department of Engineering Physics, Fabulas Laboratory, Polytechnique Montréal, 2500 Chem. de Polytechnique, Montréal, H3T 1J4, Quebec, Canada
| | - Roberto Morandotti
- Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Lionel-Boulet Blvd., Varennes, J3X 1P7, Quebec, Canada
| | - Raman Kashyap
- Department of Engineering Physics, Fabulas Laboratory, Polytechnique Montréal, 2500 Chem. de Polytechnique, Montréal, H3T 1J4, Quebec, Canada
- Department of Electrical Engineering, Fabulas Laboratory, Polytechnique Montréal, 2500 Chem. de Polytechnique, Montréal, H3T 1J4, Quebec, Canada
| | - José Azaña
- Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Lionel-Boulet Blvd., Varennes, J3X 1P7, Quebec, Canada.
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5
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Lao C, Jin X, Chang L, Wang H, Lv Z, Xie W, Shu H, Wang X, Bowers JE, Yang QF. Quantum decoherence of dark pulses in optical microresonators. Nat Commun 2023; 14:1802. [PMID: 37002215 PMCID: PMC10066214 DOI: 10.1038/s41467-023-37475-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 03/16/2023] [Indexed: 04/03/2023] Open
Abstract
Quantum fluctuations disrupt the cyclic motions of dissipative Kerr solitons (DKSs) in nonlinear optical microresonators and consequently cause timing jitter of the emitted pulse trains. This problem is translated to the performance of several applications that employ DKSs as compact frequency comb sources. Recently, device manufacturing and noise reduction technologies have advanced to unveil the quantum properties of DKSs. Here we investigate the quantum decoherence of DKSs existing in normal-dispersion microresonators known as dark pulses. By virtue of the very large material nonlinearity, we directly observe the quantum decoherence of dark pulses in an AlGaAs-on-insulator microresonator, and the underlying dynamical processes are resolved by injecting stochastic photons into the microresonators. Moreover, phase correlation measurements show that the uniformity of comb spacing of quantum-limited dark pulses is better than 1.2 × 10-16 and 2.5 × 10-13 when normalized to the optical carrier frequencies and repetition frequencies, respectively. Comparing DKSs generated in different material platforms explicitly confirms the advantages of dark pulses over bright solitons in terms of quantum-limited coherence. Our work establishes a critical performance assessment of DKSs, providing guidelines for coherence engineering of chip-scale optical frequency combs.
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Affiliation(s)
- Chenghao Lao
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China
| | - Xing Jin
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China
| | - Lin Chang
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - Heming Wang
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Zhe Lv
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China
| | - Weiqiang Xie
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106, USA
- State Key Lab of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Haowen Shu
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - Xingjun Wang
- State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China
| | - John E Bowers
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106, USA.
| | - Qi-Fan Yang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China.
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China.
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6
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Belsley A. Quantum-Enhanced Absorption Spectroscopy with Bright Squeezed Frequency Combs. PHYSICAL REVIEW LETTERS 2023; 130:133602. [PMID: 37067300 DOI: 10.1103/physrevlett.130.133602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 02/10/2023] [Accepted: 03/14/2023] [Indexed: 06/19/2023]
Abstract
Absorption spectroscopy is a widely used technique that permits the detection and characterization of gas species at low concentrations. We propose a sensing strategy combining the advantages of frequency modulation spectroscopy with the reduced noise properties accessible by squeezing the probe state. A homodyne detection scheme allows the simultaneous measurement of the absorption at multiple frequencies and is robust against dispersion across the absorption profile. We predict a significant enhancement of the signal-to-noise ratio that scales exponentially with the squeezing factor. An order of magnitude improvement beyond the standard quantum limit is possible with state-of-the-art squeezing levels facilitating high precision gas sensing.
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Affiliation(s)
- Alexandre Belsley
- Quantum Engineering Technology Labs, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1FD, United Kingdom and Quantum Engineering Centre for Doctoral Training, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1FD, United Kingdom
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7
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Lei F, Ye Z, Twayana K, Gao Y, Girardi M, Helgason ÓB, Zhao P, Torres-Company V. Hyperparametric Oscillation via Bound States in the Continuum. PHYSICAL REVIEW LETTERS 2023; 130:093801. [PMID: 36930933 DOI: 10.1103/physrevlett.130.093801] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
Optical hyperparametric oscillation based on the third-order nonlinearity is one of the most significant mechanisms to generate coherent electromagnetic radiation and produce quantum states of light. Advances in dispersion-engineered high-Q microresonators allow for generating signal waves far from the pump and decrease the oscillation power threshold to submilliwatt levels. However, the pump-to-signal conversion efficiency and absolute signal power are low, fundamentally limited by parasitic mode competition and attainable cavity intrinsic Q to coupling Q ratio, i.e., Q_{i}/Q_{c}. Here, we use Friedrich-Wintgen bound states in the continuum (BICs) to overcome the physical challenges in an integrated microresonator-waveguide system. As a result, on-chip coherent hyperparametric oscillation is generated in BICs with unprecedented conversion efficiency and absolute signal power. This work not only opens a path to generate high-power and efficient continuous-wave electromagnetic radiation in Kerr nonlinear media but also enhances the understanding of a microresonator-waveguide system-an elementary unit of modern photonics.
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Affiliation(s)
- Fuchuan Lei
- Department of Microtechnology and Nanoscience, Chalmers University of Technology SE-41296 Gothenburg, Sweden
| | - Zhichao Ye
- Department of Microtechnology and Nanoscience, Chalmers University of Technology SE-41296 Gothenburg, Sweden
| | - Krishna Twayana
- Department of Microtechnology and Nanoscience, Chalmers University of Technology SE-41296 Gothenburg, Sweden
| | - Yan Gao
- Department of Microtechnology and Nanoscience, Chalmers University of Technology SE-41296 Gothenburg, Sweden
| | - Marcello Girardi
- Department of Microtechnology and Nanoscience, Chalmers University of Technology SE-41296 Gothenburg, Sweden
| | - Óskar B Helgason
- Department of Microtechnology and Nanoscience, Chalmers University of Technology SE-41296 Gothenburg, Sweden
| | - Ping Zhao
- Department of Microtechnology and Nanoscience, Chalmers University of Technology SE-41296 Gothenburg, Sweden
| | - Victor Torres-Company
- Department of Microtechnology and Nanoscience, Chalmers University of Technology SE-41296 Gothenburg, Sweden
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8
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Nehra R, Sekine R, Ledezma L, Guo Q, Gray RM, Roy A, Marandi A. Few-cycle vacuum squeezing in nanophotonics. Science 2022; 377:1333-1337. [DOI: 10.1126/science.abo6213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
One of the most fundamental quantum states of light is the squeezed vacuum, in which noise in one of the quadratures is less than the standard quantum noise limit. In nanophotonics, it remains challenging to generate, manipulate, and measure such a quantum state with the performance required for a wide range of scalable quantum information systems. Here, we report the development of a lithium niobate–based nanophotonic platform to demonstrate the generation and all-optical measurement of squeezed states on the same chip. The generated squeezed states span more than 25 terahertz of bandwidth supporting just a few optical cycles. The measured 4.9 decibels of squeezing surpass the requirements for a wide range of quantum information systems, demonstrating a practical path toward scalable ultrafast quantum nanophotonics.
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Affiliation(s)
- Rajveer Nehra
- Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ryoto Sekine
- Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Luis Ledezma
- Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Qiushi Guo
- Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Robert M. Gray
- Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Arkadev Roy
- Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Alireza Marandi
- Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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9
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Lu HH, Myilswamy KV, Bennink RS, Seshadri S, Alshaykh MS, Liu J, Kippenberg TJ, Leaird DE, Weiner AM, Lukens JM. Bayesian tomography of high-dimensional on-chip biphoton frequency combs with randomized measurements. Nat Commun 2022; 13:4338. [PMID: 35896534 PMCID: PMC9329349 DOI: 10.1038/s41467-022-31639-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 06/10/2022] [Indexed: 11/20/2022] Open
Abstract
Owing in large part to the advent of integrated biphoton frequency combs, recent years have witnessed increased attention to quantum information processing in the frequency domain for its inherent high dimensionality and entanglement compatible with fiber-optic networks. Quantum state tomography of such states, however, has required complex and precise engineering of active frequency mixing operations, which are difficult to scale. To address these limitations, we propose a solution that employs a pulse shaper and electro-optic phase modulator to perform random operations instead of mixing in a prescribed manner. We successfully verify the entanglement and reconstruct the full density matrix of biphoton frequency combs generated from an on-chip Si3N4 microring resonator in up to an 8 × 8-dimensional two-qudit Hilbert space, the highest dimension to date for frequency bins. More generally, our employed Bayesian statistical model can be tailored to a variety of quantum systems with restricted measurement capabilities, forming an opportunistic tomographic framework that utilizes all available data in an optimal way. Full tomography of biphoton frequency comb states requires frequency mixing operations which are hard to scale. Here, the authors propose and demonstrate a protocol exploiting advanced Bayesian statistical methods and randomized measurements coming from complex mode mixing in electro-optic phase modulators.
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Affiliation(s)
- Hsuan-Hao Lu
- Quantum Information Science Section, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA. .,School of Electrical and Computer Engineering and Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, 47907, USA.
| | - Karthik V Myilswamy
- School of Electrical and Computer Engineering and Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, 47907, USA.
| | - Ryan S Bennink
- Quantum Information Science Section, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Suparna Seshadri
- School of Electrical and Computer Engineering and Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, 47907, USA
| | - Mohammed S Alshaykh
- School of Electrical and Computer Engineering and Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, 47907, USA.,Electrical Engineering Department, King Saud University, Riyadh, 11421, Saudi Arabia
| | - Junqiu Liu
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Tobias J Kippenberg
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Daniel E Leaird
- School of Electrical and Computer Engineering and Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, 47907, USA.,Torch Technologies, supporting AFRL/RW, Eglin Air Force Base, Shalimar, FL, 32542, USA
| | - Andrew M Weiner
- School of Electrical and Computer Engineering and Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, 47907, USA
| | - Joseph M Lukens
- Quantum Information Science Section, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
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10
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Han D, Wang N, Wang M, Qin Z, Su X. Remote preparation and manipulation of squeezed light. OPTICS LETTERS 2022; 47:3295-3298. [PMID: 35776609 DOI: 10.1364/ol.463697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
Remote state preparation enables one to create and manipulate a quantum state based on the shared entanglement between distant nodes. Here, we experimentally demonstrate remote preparation and manipulation of squeezed light. By performing a homodyne projective measurement on one mode of the continuous variable entangled state at Alice's station, a squeezed state is created at Bob's station. Moreover, rotation and displacement operations are applied on the prepared squeezed state by changing the projective parameters on Alice's state. We also show that the remotely prepared squeezed state is robust against loss and N - 1 squeezed states can be remotely prepared based on an N-mode continuous variable Greenberger-Horne-Zeilinger-like state. Our results verify the entanglement-based model used in security analysis of quantum key distribution with continuous variables and have potential application in remote quantum information processing.
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11
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Biele J, Tasker JF, Silverstone JW, Matthews JCF. Shot-noise limited homodyne detection for MHz quantum light characterisation in the 2 µm band. OPTICS EXPRESS 2022; 30:7716-7724. [PMID: 35299527 DOI: 10.1364/oe.450217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
Characterising quantum states of light in the 2 µm band requires high-performance shot-noise limited detectors. Here, we present the characterisation of a homodyne detector that we use to observe vacuum shot-noise via homodyne measurement with a 2.07 µm pulsed mode-locked laser. The device is designed primarily for pulsed illumination. It has a 3-dB bandwidth of 13.2 MHz, total conversion efficiency of 57% at 2.07 µm, and a common-mode rejection ratio of 48 dB at 39.5 MHz. The detector begins to saturate at 1.8 mW with 9 dB of shot-noise clearance at 5 MHz. This demonstration enables the characterisation of megahertz-quantum optical behaviour in the 2 µm band and provides a guide of how to design a 2 µm homodyne detector for quantum applications.
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12
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Tian Y, Sun X, Wang Y, Li Q, Tian L, Zheng Y. Cavity enhanced parametric homodyne detection of a squeezed quantum comb. OPTICS LETTERS 2022; 47:533-536. [PMID: 35103674 DOI: 10.1364/ol.446645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/19/2021] [Indexed: 06/14/2023]
Abstract
A squeezed state with higher-order sidebands is a valuable quantum resource for channel multiplexing quantum communication. However, balanced homodyne detection used in nonclassical light detection has a trade-off performance between the detection bandwidth and clearance, in which the verification of a highly squeezing factor faces a challenge. Here, we construct two optical parametric amplifiers with cavity enhancement; one is for the generation of a -10.5 dB squeezed vacuum state, and the other is for all-optical phase-sensitive parametric homodyne detection. Finally, -6.5 dB squeezing at the carrier with 17 pairs of squeezing sidebands (bandwidth of 156 GHz) is directly and simultaneously observed. In particular, for the cavity-enhanced parametric oscillation and detection processes, we analyze the limiting factors of the detectable bandwidth and measurement deviation from the generated value, which indicates that the length difference and propagation loss between two optical parametric amplifiers should be as small as possible to improve the detection performance. The experimental results confirm our theoretical analysis.
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13
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Kim D, Han S, Kim DG, Ko K, Choi DY, Lee H. Two-point coupling method to independently control coupling efficiency at different wavelengths. OPTICS LETTERS 2022; 47:106-109. [PMID: 34951891 DOI: 10.1364/ol.443734] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/28/2021] [Indexed: 06/14/2023]
Abstract
To efficiently access light waves confined in a high-quality-factor (Q) microcavity over a wide spectral range, it is necessary to independently control coupling efficiency at different wavelengths. Here we suggest an approach to add a degree of freedom to control the coupling efficiency based on a two-point coupling geometry. By changing the phase difference between two paths connecting two coupling points, various combinations of coupling efficiencies at multiple wavelengths can be achieved. An analytic model describing the coupling property is derived and confirmed by experimental results. It is also shown that the coupling property can be modified by adjusting the effective refractive index difference between a waveguide and a resonator.
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