Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2306.00098 · Physical Review A

Enhanced-sensitivity interferometry with phase-sensitive unbiased multiports

Christopher R. Schwarze, David S. Simon, Alexander V. Sergienko

Published May 25, 2023• 14 citations
arXivHTMLPDF

Abstract

Here we introduce interferometric devices by combining optical feedback (cavities) with unbiased multiports, which, unlike traditional beam dividers, allow light to reflect back out of the port from which it originated. By replacing the traditional, directionally biased beam-splitter in a Michelson interferometer with an unbiased multiport, the functional dependence of the scattering amplitudes changes. As a result, the derivative of transmittance with respect to an external phase perturbation can be made substantially large. This significantly enhances the resolution of phase measurement and allows the phase response curves to be altered in real time by tuning an externally controllable phase shift.

DOI
10.1103/physreva.107.052615

Related papers

Super-resolution interferometric phase measurement with directionally-unbiased linear-optical devices

Christopher R. Schwarze, David S. Simon, Abdoulaye Ndao +1 more

A beam-splitter forbids input light from exiting the input port. We introduce a four-port linear scatterer without this restriction, establishing an alternate approach to cavity interferometry. The Michelson configuration enables super-resolution phase measurements without post-selection.

•Jan 1, 2024•0 citations

Strain sensitivity enhancement in a Grover-Michelson interferometer

Anthony D. Manni, Christopher R. Schwarze, David S. Simon +2 more

The Michelson interferometric phase detection resolution can be enhanced by replacing conventional beam splitters with novel directionally unbiased four-port scatterers, such as Grover coins. We present a quantitative analysis of the noise-to-signal ratio of sideband frequencies generated by gravitational wave-induced phase perturbations in a Grover-Michelson interferometer (GMI). We discuss the principles of GMI signal enhancement and demonstrate how combining this configuration with additional light-recycling arrangements further enhances the performance.

quant-pharXiv:2512.08638•Dec 10, 2025

Experimental demonstration of enhanced-sensitivity Grover-Michelson interferometer for quantum sensing

Christopher R. Schwarze, David S. Simon, Anthony D. Manni +2 more

We construct and characterize a Grover coin with tabletop optics. This directionally unbiased higher-dimensional four-port scatterer replaces a standard beam-splitter in the Michelson interferometer, resulting in a sharper phase response without reducing visibility.

•Jan 1, 2025•0 citations

Interferometry and higher-dimensional phase measurements using directionally unbiased linear optics

David S. Simon, Christopher R. Schwarze, Alexander V. Sergienko

Grover multiports are higher-dimensional generalizations of beam splitters, in which input to any one of the four ports has equal probability of exiting at any of the same four ports, including the input port. In this paper, we demonstrate that interferometers built from such multiports have novel features. For example, when combined with two-photon input and coincidence measurements, it is shown that such interferometers have capabilities beyond those of standard beam-splitter-based interferometers, such as easily controlled interpolation between Hong-Ou-Mandel (HOM) and anti-HOM behavior. Further, it is shown that the Grover-based analog of the Mach-Zehnder interferometer can make three separate phase measurements simultaneously. By arranging the transmission lines between the two multiports to lie in different planes, the same interferometer acts as a higher-dimensional Sagnac interferometer, allowing rotation rates about three different axes to be measured with a single device.

arXiv:2209.09414•Physical Review A•Sep 15, 2022•11 citations

Enhancing Phase Sensitivity in Mach–Zehnder Interferometers for Arbitrary Input States

Hongbin Liang, Jiancheng Pei, Xiaoguang Wang

To enhance the phase sensitivity of Mach–Zehnder interferometers, we use a tunable phase shift before the light beams are injected into the interferometer. The analytical result of the optimal phase shift is obtained, which only depends on the initial input states. For a non-zero optimal phase shift, the phase sensitivity of the interferometers in the output ports is always enhanced. We can achieve this enhancement for most states, including entangled and mixed states. The optimal phase shift is exhibited in three examples. Compared to previous methods, this scheme provides a general way to improve phase sensitivity and could find wide applications in optical phase estimations.

Chinese Physics Letters•Jul 1, 2020•1 citation

Grover–Sagnac interferometer

Christopher R. Schwarze, Anthony D. Manni, David S. Simon +2 more

We demonstrate a nontraditional design of the Sagnac interferometer by replacing the commonly used beam splitter with a linear-optical Grover multiport. This substitution creates a pole at the origin of the device parameter space, with an associated resonance in the output intensity. The structure of this resonance is dictated only by the nonreciprocal portion of the phase acquired in the Sagnac loop. This property directly results from adopting the more symmetric and higher-dimensional central scattering coin, and it allows for a different approach to registering and detecting the nonreciprocal Sagnac phase. This parameter may be extracted from the width of a peak or dip in the interferogram, instead of tracing small changes in power as in traditional Sagnac interferometry. We discuss how losses affect the system and potential metrological applications.

arXiv:2501.14049•Journal of the Optical Society of America A•Jan 7, 2025•4 citations
Here we introduce interferometric devices by combining optical feedback (cavities) with unbiased multiports, which, unlike traditional beam dividers, allow light to reflect back out of the port from which it originated. By replacing the traditional, directionally biased beam-splitter in a Michelson interferometer with an unbiased multiport, the functional dependence of the scattering amplitudes changes. As a result, the derivative of transmittance with respect to an external phase perturbation can be made substantially large. This significantly enhances the resolution of phase measurement and allows the phase response curves to be altered in real time by tuning an externally controllable phase shift.
The Michelson interferometric phase detection resolution can be enhanced by replacing conventional beam splitters with novel directionally unbiased four-port scatterers, such as Grover coins. We present a quantitative analysis of the noise-to-signal ratio of sideband frequencies generated by gravitational wave-induced phase perturbations in a Grover-Michelson interferometer (GMI). We discuss the principles of GMI signal enhancement and demonstrate how combining this configuration with additional light-recycling arrangements further enhances the performance.
Grover multiports are higher-dimensional generalizations of beam splitters, in which input to any one of the four ports has equal probability of exiting at any of the same four ports, including the input port. In this paper, we demonstrate that interferometers built from such multiports have novel features. For example, when combined with two-photon input and coincidence measurements, it is shown that such interferometers have capabilities beyond those of standard beam-splitter-based interferometers, such as easily controlled interpolation between Hong-Ou-Mandel (HOM) and anti-HOM behavior. Further, it is shown that the Grover-based analog of the Mach-Zehnder interferometer can make three separate phase measurements simultaneously. By arranging the transmission lines between the two multiports to lie in different planes, the same interferometer acts as a higher-dimensional Sagnac interferometer, allowing rotation rates about three different axes to be measured with a single device.
To enhance the phase sensitivity of Mach–Zehnder interferometers, we use a tunable phase shift before the light beams are injected into the interferometer. The analytical result of the optimal phase shift is obtained, which only depends on the initial input states. For a non-zero optimal phase shift, the phase sensitivity of the interferometers in the output ports is always enhanced. We can achieve this enhancement for most states, including entangled and mixed states. The optimal phase shift is exhibited in three examples. Compared to previous methods, this scheme provides a general way to improve phase sensitivity and could find wide applications in optical phase estimations.
We demonstrate a nontraditional design of the Sagnac interferometer by replacing the commonly used beam splitter with a linear-optical Grover multiport. This substitution creates a pole at the origin of the device parameter space, with an associated resonance in the output intensity. The structure of this resonance is dictated only by the nonreciprocal portion of the phase acquired in the Sagnac loop. This property directly results from adopting the more symmetric and higher-dimensional central scattering coin, and it allows for a different approach to registering and detecting the nonreciprocal Sagnac phase. This parameter may be extracted from the width of a peak or dip in the interferogram, instead of tracing small changes in power as in traditional Sagnac interferometry. We discuss how losses affect the system and potential metrological applications.