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Nakamura T, Nomura T, Endo M, Sakaguchi A, Ruofan H, Kashiwazaki T, Umeki T, Takase K, Asavanant W, Yoshikawa JI, Furusawa A. Long-term stability of squeezed light in a fiber-based system using automated alignment. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:093004. [PMID: 39345166 DOI: 10.1063/5.0203988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 09/03/2024] [Indexed: 10/01/2024]
Abstract
Providing a cloud service for optical quantum computing requires stabilizing the optical system for extended periods. It is advantageous to construct a fiber-based system, which does not require spatial alignment. However, fiber-based systems are instead subject to fiber-specific instabilities. For instance, there are phase drifts due to ambient temperature changes and external disturbances and polarization fluctuations due to the finite polarization extinction ratio of fiber components. Here, we report the success of measuring squeezed light with a fiber system for 24 h. To do this, we introduce stabilization mechanics to suppress fluctuations in the fiber system and an integrated controller to automatically align the entire system. The squeezed light at a wavelength of 1545.3 nm is measured every 2 min, where automated alignments are inserted every 30 min. The squeezing levels with an average of -4.42 dB are recorded with an extremely small standard deviation of 0.08 dB over 24 h. With the technologies developed here, we can build complicated optical setups with the fiber-based system and operate them automatically for extended periods, which is promising for cloud service of quantum computation.
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Affiliation(s)
- Tomohiro Nakamura
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Takefumi Nomura
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Mamoru Endo
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, 2-1, Hirosawa, Wako 351-0198, Saitama, Japan
| | - Atsushi Sakaguchi
- Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, 2-1, Hirosawa, Wako 351-0198, Saitama, Japan
| | - He Ruofan
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Takahiro Kashiwazaki
- NTT Device Technology Labs, NTT Corporation, 3-1, Morinosato Wakamiya, Atsugi 243-0198, Kanagawa, Japan
| | - Takeshi Umeki
- NTT Device Technology Labs, NTT Corporation, 3-1, Morinosato Wakamiya, Atsugi 243-0198, Kanagawa, Japan
| | - Kan Takase
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, 2-1, Hirosawa, Wako 351-0198, Saitama, Japan
| | - Warit Asavanant
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, 2-1, Hirosawa, Wako 351-0198, Saitama, Japan
| | - Jun-Ichi Yoshikawa
- Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, 2-1, Hirosawa, Wako 351-0198, Saitama, Japan
| | - Akira Furusawa
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, 2-1, Hirosawa, Wako 351-0198, Saitama, Japan
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Nguyen C, Bréelle E, Barsuglia M, Capocasa E, De Laurentis M, Sequino V, Sorrentino F. Thermally controlled optical resonator for vacuum squeezed states separation. APPLIED OPTICS 2022; 61:5226-5236. [PMID: 36256205 DOI: 10.1364/ao.459190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/20/2022] [Indexed: 06/16/2023]
Abstract
Future gravitational-wave detectors will use frequency-dependent squeezed vacuum states to obtain broadband reduction of quantum noise. Quantum noise is one of the major limitations to the sensitivity of these detectors. Advanced LIGO+, Advanced Virgo+, and KAGRA plan to generate frequency-dependent squeezed states by coupling a frequency-independent squeezed light state with a filter cavity. An alternative technique is under consideration, based on conditional squeezing with quantum entanglement: Einstein-Podolsky-Rosen (EPR) squeezing. In the EPR scheme, two vacuum entangled states, the signal field at ω0 and the idler field at ω0+Δ, must be spatially separated with an optical resonator and sent to two separate homodyne detectors. In this framework, we have designed and tested a solid Fabry-Perot etalon, to be used in an EPR table-top experiment prototype, thermally controlled without the use of a control probe optical beam. This device can also be used in optical experiments where the use of a bright beam to control an optical resonator is not possible, or where a simpler optical device is preferred.
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Abstract
Injecting optical squeezed states of light, a technique known as squeezing, is now a tool for gravitational wave detection. Its ability to reduce quantum noise is helping to reveal more gravitational wave transients, expanding the catalog of observations in the last observing run. This review introduces squeezing and its history in the context of gravitational-wave detectors. It overviews the benefits, limitations and methods of incorporating squeezing into advanced interferometers, emphasizing the most relevant details for astrophysics instrumentation.
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