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

Acta Physica Sinica

Locking the phase of balanced homodyne detection system for squeezed light

Zhang Yan, Xudong Yu, Ke Di Ma, Wei Li, Jing Zhang

Published Jan 1, 2013• 8 citations
Publisher

Abstract

The balanced homodyne detection technique is an important method to detect the quantum light field. The signal light injected into the phase sensitive optical parameter amplifier (OPA) is phase modulated. The output squeezed light of OPA is detected by the balanced homodyne detection system. When the phase sensitive OPA is operated at parametric amplification and deamplification respectively, we can judge which quadrature component of the quantum light field is measured by observing the modulation signal. We can demodulate the phase modulation signal to achieve the error signal, which is used to lock the relative phase of zero between the local and the quantum light fields (corresponding to the quadrature-amplitude of the unknown light field).

DOI
10.7498/aps.62.084204

Related papers

Design and simulation of a 300 MHz Balanced Homodyne Detector for quantum photonics

Jiayi Yang

Balanced Homodyne Detection (BHD), introduced in the 1970s, enables highly sensitive detection of phase and amplitude variations in weak light. Initially developed as an advanced optical detection technique, it rapidly became essential in quantum optics for accurately quantifying quadrature components and detecting squeezed states at the shot-noise limit. Today, BHD plays a critical role in diverse fields such as high-precision quantum metrology, gigabit speed optical communications, gravitational wave detection, and large-scale quantum information systems. In this study, a BHD simulation was implemented with a 90 phase difference between the local oscillator and the signal, thus enabling the extraction of the phase quadratureP^component of the optical field.

Advances in Engineering Innovation•Jul 10, 2025•0 citations

Experimental study of balanced optical homodyne and heterodyne detection by controlling sideband modulation

Li We

We experimentally study optical homodyne and heterodyne detections with the same setup, which is flexible to manipulate the signal sideband modulation. When the modulation only generates a single signal sideband, the light field measurement by mixing the single sideband at ω0 ±? with a strong local oscillator at the carrier frequency ω0on a beam splitter becomes balanced heterodyne detection. When two signal sidebands at ω0 ±? are generated and the relative phase of the two sidebands is locked, this measurement corresponds to optical balanced homodyne detection. With this setup, we may confirm directly that the signal-to-noise ratio with heterodyne detection is two-fold worse than that with homodyne detection. This work will have important applications in quantum state measurement and quantum information.

Science in China. Series G, Physics, mechanics & astronomy/Science in China. Series G, Physics, Mechanics & Astronomy•Jan 1, 2015•0 citations

Theoretical study on balanced homodyne detection technique in preparation of squeezed states of light

Wenyan Qu, Fei Feng, Jiazheng Song +1 more

We analyze the balanced homodyne detection technique in the detection of squeezed light, which is controlled by dither locking scheme. We discuss how the balanced homodyne detection efficiency influences the detected degree of squeezing. Also, fluctuation in the relative phase between the local beam and the squeezed light is discussed, since a little phase fluctuation would decrease the detected degree of squeezing greatly. Then, the dither locking technique is studied in detail, which is used to lock the relative phase between the local beam and the squeezed light. The simulation experiments and theoretically results show that the balanced homodyne detection technique and the dither locking scheme are efficient methods to get more accurate degree of squeezing in the preparation of the squeezed states of light.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Aug 16, 2013•0 citations

Balanced Homodyne Detector With Independent Phase Control and Noise Detection Branches

JinRong Wang, Wenhui Zhang, Long Tian +4 more

Squeezed state light is a fundamental resource for many quantum optics experiments. Important applications like quantum-enhanced magnetometer and quantum key distribution, require the squeezing level as high as possible. In balanced homodyne detection, the detector output is directly proportional to the noise of the squeezed beam. The detected quadrature is dependent on the relative phase between the squeezed beam and local oscillator. Here, we present a balanced homodyne detector (BHD) with independent phase control and noise detection branches. The independence between the phase control and noise detection branches is experimentally verified, the two branches are independently optimized according to the practical requirements. With the BHD, a bright squeezed light at 1550 nm with quantum noise reduction of 10.3 dB is directly detected. After stabilizing the relative phase between the squeezed states and local oscillator by the phase locking branch of the BHD, the fluctuation of the noise suppression is ±0.2 dB by 1-h testing time.

IEEE Access•Jan 1, 2019•9 citations

Quadrature-Averaged Homodyne Detection for Estimating Cavity Parameters

Giada R. La Gala, Arvind Shankar Kumar, Rick Leijssen +2 more

Balanced homodyne interferometry is a well-known detection technique that allows for sensitive characterization of light fields. Conventionally a homodyne interferometer is operated by locking the relative phase of a reference beam to the signal beam by means of an active feedback loop. A less often used method is to perform a slow continuous modulation of the reference beam arm length that corresponds to averaging all relative phases during the measurement. Here we show theoretically and experimentally that this quadrature averaging can be advantageous in estimating the parameters of a resonant optical cavity. We demonstrate that the averaging turns the transduction function, from cavity frequency fluctuations into the interferometer signal, into a simple function of the laser detuning that, notably, does not depend on the parameters of possible nonresonant channels present in the system. The method needs no active feedback and gives results that are easy to interpret. Moreover, the phase-averaged measurement allows characterization of the absolute magnitude of a cavity frequency modulation.

Physical Review Applied•Jun 2, 2023•2 citations

Phase locking of squeezed vacuum generated by a single-pass optical parametric amplifier

Yoshitaka Taguchi, Kenichi Oguchi, Zicong Xu +5 more

In high-precision optical measurements, squeezed vacuum states are a promising resource for reducing the shot noise. To utilize a squeezed vacuum, it is important to lock the phase of the local oscillator (LO) to the squeezed light. The coherent control sideband (CCSB) scheme has been established for the precise phase locking, while the previous CCSB scheme was designed for the squeezed vacuum generated with an optical parametric oscillator (OPO). Thus the previous CCSB scheme is not applicable to squeezing by a single-pass optical parametric amplifier (OPA), which is attractive for generating broadband squeezed vacuum states. In this study, we propose a variant of CCSB scheme, which is applicable to the squeezing by single-pass OPA. In this scheme, we inject pump light and frequency-shifted signal light into an OPA crystal in the same way as the previous CCSB scheme. The parametric process in the OPA crystal generates a squeezed vacuum, amplifies the signal light, generates an idler light, and causes the pump depletion reflecting the interference of the amplified signal light and the idler light. Through the lock-in detection of the pump depletion, we can phase-lock the injected signal light to the pump light. Then, after the heterodyne detection of the signal and the idler light, we get the error signal of LO and realize the precise phase locking of LO to the squeezed quadrature. We show the feasibility of the proposed scheme by deriving the signal-to-noise ratio (SNR) of the modulated pump signal. We experimentally demonstrate the proposed scheme on pulsed squeezing by a single-pass OPA.

Optics Express•Feb 11, 2022•13 citations
The balanced homodyne detection technique is an important method to detect the quantum light field. The signal light injected into the phase sensitive optical parameter amplifier (OPA) is phase modulated. The output squeezed light of OPA is detected by the balanced homodyne detection system. When the phase sensitive OPA is operated at parametric amplification and deamplification respectively, we can judge which quadrature component of the quantum light field is measured by observing the modulation signal. We can demodulate the phase modulation signal to achieve the error signal, which is used to lock the relative phase of zero between the local and the quantum light fields (corresponding to the quadrature-amplitude of the unknown light field).
Balanced Homodyne Detection (BHD), introduced in the 1970s, enables highly sensitive detection of phase and amplitude variations in weak light. Initially developed as an advanced optical detection technique, it rapidly became essential in quantum optics for accurately quantifying quadrature components and detecting squeezed states at the shot-noise limit. Today, BHD plays a critical role in diverse fields such as high-precision quantum metrology, gigabit speed optical communications, gravitational wave detection, and large-scale quantum information systems. In this study, a BHD simulation was implemented with a 90 phase difference between the local oscillator and the signal, thus enabling the extraction of the phase quadratureP^component of the optical field.
We experimentally study optical homodyne and heterodyne detections with the same setup, which is flexible to manipulate the signal sideband modulation. When the modulation only generates a single signal sideband, the light field measurement by mixing the single sideband at ω0 ±? with a strong local oscillator at the carrier frequency ω0on a beam splitter becomes balanced heterodyne detection. When two signal sidebands at ω0 ±? are generated and the relative phase of the two sidebands is locked, this measurement corresponds to optical balanced homodyne detection. With this setup, we may confirm directly that the signal-to-noise ratio with heterodyne detection is two-fold worse than that with homodyne detection. This work will have important applications in quantum state measurement and quantum information.
We analyze the balanced homodyne detection technique in the detection of squeezed light, which is controlled by dither locking scheme. We discuss how the balanced homodyne detection efficiency influences the detected degree of squeezing. Also, fluctuation in the relative phase between the local beam and the squeezed light is discussed, since a little phase fluctuation would decrease the detected degree of squeezing greatly. Then, the dither locking technique is studied in detail, which is used to lock the relative phase between the local beam and the squeezed light. The simulation experiments and theoretically results show that the balanced homodyne detection technique and the dither locking scheme are efficient methods to get more accurate degree of squeezing in the preparation of the squeezed states of light.
Squeezed state light is a fundamental resource for many quantum optics experiments. Important applications like quantum-enhanced magnetometer and quantum key distribution, require the squeezing level as high as possible. In balanced homodyne detection, the detector output is directly proportional to the noise of the squeezed beam. The detected quadrature is dependent on the relative phase between the squeezed beam and local oscillator. Here, we present a balanced homodyne detector (BHD) with independent phase control and noise detection branches. The independence between the phase control and noise detection branches is experimentally verified, the two branches are independently optimized according to the practical requirements. With the BHD, a bright squeezed light at 1550 nm with quantum noise reduction of 10.3 dB is directly detected. After stabilizing the relative phase between the squeezed states and local oscillator by the phase locking branch of the BHD, the fluctuation of the noise suppression is ±0.2 dB by 1-h testing time.
Balanced homodyne interferometry is a well-known detection technique that allows for sensitive characterization of light fields. Conventionally a homodyne interferometer is operated by locking the relative phase of a reference beam to the signal beam by means of an active feedback loop. A less often used method is to perform a slow continuous modulation of the reference beam arm length that corresponds to averaging all relative phases during the measurement. Here we show theoretically and experimentally that this quadrature averaging can be advantageous in estimating the parameters of a resonant optical cavity. We demonstrate that the averaging turns the transduction function, from cavity frequency fluctuations into the interferometer signal, into a simple function of the laser detuning that, notably, does not depend on the parameters of possible nonresonant channels present in the system. The method needs no active feedback and gives results that are easy to interpret. Moreover, the phase-averaged measurement allows characterization of the absolute magnitude of a cavity frequency modulation.
In high-precision optical measurements, squeezed vacuum states are a promising resource for reducing the shot noise. To utilize a squeezed vacuum, it is important to lock the phase of the local oscillator (LO) to the squeezed light. The coherent control sideband (CCSB) scheme has been established for the precise phase locking, while the previous CCSB scheme was designed for the squeezed vacuum generated with an optical parametric oscillator (OPO). Thus the previous CCSB scheme is not applicable to squeezing by a single-pass optical parametric amplifier (OPA), which is attractive for generating broadband squeezed vacuum states. In this study, we propose a variant of CCSB scheme, which is applicable to the squeezing by single-pass OPA. In this scheme, we inject pump light and frequency-shifted signal light into an OPA crystal in the same way as the previous CCSB scheme. The parametric process in the OPA crystal generates a squeezed vacuum, amplifies the signal light, generates an idler light, and causes the pump depletion reflecting the interference of the amplified signal light and the idler light. Through the lock-in detection of the pump depletion, we can phase-lock the injected signal light to the pump light. Then, after the heterodyne detection of the signal and the idler light, we get the error signal of LO and realize the precise phase locking of LO to the squeezed quadrature. We show the feasibility of the proposed scheme by deriving the signal-to-noise ratio (SNR) of the modulated pump signal. We experimentally demonstrate the proposed scheme on pulsed squeezing by a single-pass OPA.