Optimal phase measurements in a lossy Mach–Zehnder interferometer with coherent input light

Wenfeng Huang; Xinyun Liang; Chun-Hua Yuan; Weiping Zhang; L.Q. Chen

Results in Physics (Jul 2023)

Optimal phase measurements in a lossy Mach–Zehnder interferometer with coherent input light

Wenfeng Huang,
Xinyun Liang,
Chun-Hua Yuan,
Weiping Zhang,
L.Q. Chen

Affiliations

Wenfeng Huang: State Key Laboratory of Precision Spectroscopy, Quantum Institute for Light and Atoms, Department of Physics and Electronic Science, East China Normal University, Shanghai 200062, China
Xinyun Liang: State Key Laboratory of Precision Spectroscopy, Quantum Institute for Light and Atoms, Department of Physics and Electronic Science, East China Normal University, Shanghai 200062, China
Chun-Hua Yuan: State Key Laboratory of Precision Spectroscopy, Quantum Institute for Light and Atoms, Department of Physics and Electronic Science, East China Normal University, Shanghai 200062, China; Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China; Corresponding author.
Weiping Zhang: Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China; School of Physics and Astronomy, and Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
L.Q. Chen: State Key Laboratory of Precision Spectroscopy, Quantum Institute for Light and Atoms, Department of Physics and Electronic Science, East China Normal University, Shanghai 200062, China; Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China; Corresponding author at: State Key Laboratory of Precision Spectroscopy, Quantum Institute for Light and Atoms, Department of Physics and Electronic Science, East China Normal University, Shanghai 200062, China.

Journal volume & issue: Vol. 50
p. 106574

Abstract

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This work discusses the single-intensity and difference-intensity detection schemes for lossy Mach–Zehnder Interferometer (MZI) and gives the corresponding optimal conditions to achieve the best phase measurements. The interferometer is fed by a coherent state in one port and a vacuum state in the other. When the core parameters (reflectivities, phase difference) are optimal, the phase sensitivity of these two detection schemes can reach a generalized precision bound: the standard interferometric limit (SIL). In the experiment, we design an MZI with adjustable beam splitters to verify the phase sensitivity optimization compared to the conventional MZI with 50:50 beam splitters. The sensitivity improvements at loss rates from 0.4 to 0.998 are demonstrated based on difference-intensity detection, matching the theoretical results well. With a loss up to 0.998 in one arm, we achieve a sensitivity improvement of 2.5 dB by adjusting reflectivity, which equates to a 5.5 dB sensitivity improvement in single-intensity detection. Such optimal phase measurement methods provide practical solutions for the correct use of resources in lossy interferometers.

Published in Results in Physics

ISSN: 2211-3797 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Physics
Website: http://www.journals.elsevier.com/results-in-physics/

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