© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Mediciones de ruido en un detector balanceado homodino para la reconstrucción de la función de Wigner de estados coherentes y de vacío

Samuel Esteban Sánchez Rodríguez

Published Jan 27, 2026• 0 citations

Abstract

The Wigner function is a quasi-probability distribution of quantum states of light that describes the probability amplitude of any state through their marginal distribution. The Wigner function can be reconstructed through quantum tomography which uses the information obtained from light quadratures to reconstruct a 3d image of the Wigner function. Light quadratures can be obtained by means of balanced homodyne detection (BHD). BHD uses a controlled interference between the quantum field to be characterized and a local oscillator, which is a coherent source with well-defined frequency and phase. The main feature of a BHD is its ability to measure extremely small noise signals, even below the quantum vacuum limit for squezeed light. To obtain precise measurements in BHD it is necessary to characterize the noise sources in the electronics of the BHD such as Johnson noise and fundamental noises such as shot noise. To characterize the noise in the BHD, time based and frequency-based measurements were performed to find the quantum to classical noise ratio (QCNR). QCNR measures the capacity of the BHD to distinguish quantum noise. A high QCNR allows us to make reliable measurements of the light quadratures. For this project we developed a circuit based on the one presented by Lang et al. in low noise balanced homodyne detector for quantum noise measurements.

Related papers

Design and characterization of wideband balanced homodyne detectors for quantum homodyne tomography

Erick Barrios Barocio

This thesis reports the realization and applications of a versatile wideband balanced homodyne detector operating in the time domain and intended for Quantum Optical Tomography. The detector can work with high repetition rate lasers used for the production and measurement of the electric field quadratures of quantum states of light. Full characterization of the detector by shot-noise measurements and by verifying its capability to reconstruct the density matrix and Wigner function of various states of interest is given. By overcoming photodiodes response mismatch, high frequency electronics issues and by choosing an appropriate optical set-up, a high level of common mode suppression (52.4dB) and a low electronic noise gave a shot-to-electronic noise ratio of I3dB for a Local Oscillator with 6.2 x 108 photons-per-pulse on a ~ 100MHz bandwidth. Results for the characterization of a single-photon Fock state are presented. An average efficiency of 56% was obtained for the generation/detection of the state.

•Jan 1, 2012•0 citations

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

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

Quantum tomography for time domain Balanced Homodyne Detection with high electronic noise

Martina Esposito, Daniele Fausti, Stefano Olivares +6 more

Here we report on the design, construction and characterization of a time domain Balanced Homodyne Detection apparatus operating in the regime of high electronic noise. The experimental setup has been commissioned by studying coherent ultrashort ( ∼ 80 fs) light pulses using Pattern-function Quantum Tomography. Furthermore, we proved that the electronic noise can be treated as a detector inefficiency showing the effectiveness of this approach by measuring light coherent states with different energies. In Quantum Mechanics the measurement of the state of a physical system implies to estimate the expectation value of any observable of the system. For a generic operator the expectation value is obtained starting from the measurement of an ensemble of observables defined “quorum ” 1. In particular, for the electromagnetic field the quorum is a continuum set of the field quadra-tures2,3. Balanced Homodyne Detection (BHD) is an experimen-tal method for measuring a discrete set of the field

•Jan 11, 2013•1 citation

1.2-GHz Balanced Homodyne Detector for Continuous-Variable Quantum Information Technology

Xiaoxiong Zhang, Yichen Zhang, Zhengyu Li +2 more

Balanced homodyne detector (BHD) that can measure the field quadratures of coherent states has been widely used in a range of quantum information technologies. Generally, the BHD tends to suffer from narrow bands and an expanding bandwidth behavior usually traps into a compromise with the gain, electronic noise, and quantum to classical noise ratio, etc. In this paper, we design and construct a wideband BHD based on radio frequency and integrated circuit technology. Our BHD shows bandwidth behavior up to 1.2 GHz and its quantum to classical noise ratio is around 18 dB. Simultaneously, the BHD has a linear performance with a gain of 4.86 k and its common mode rejection ratio has also been tested as 57.9 dB. With this BHD, the secret key rate of continuous-variable quantum key distribution system has a potential to achieve 66.55 Mb/s and 2.87 Mb/s, respectively, at the transmission distance of 10 and 45 km. Besides, with this BHD, the generation rate of quantum random number generator could reach up to 6.53 Gb/s.

arXiv:1806.09393•IEEE photonics journal•Aug 23, 2018•99 citations

A 600 MHz Balanced Homodyne Detector for Quantum Information Processing

Tianxiang Zhang, Yundi Huang, Xiangyu Wang +2 more

Balanced homodyne detector (BHD) has been widely used in quantum information processing. In this paper, we design a wide bandwidth BHD and implement an optical layout to test the performance of our BHD. The test results show that the bandwidth is about 600 MHz, the quantum to classical noise ratio (QCNR) is 15.2 dB and the common mode rejection ratio (CMRR) is 41.16 dB. The performance of BHD shows that it can meet the requirements of high-speed applications in quantum information processing.

Advances in Engineering Technology Research•May 13, 2022•0 citations

The Wigner function is a quasi-probability distribution of quantum states of light that describes the probability amplitude of any state through their marginal distribution. The Wigner function can be reconstructed through quantum tomography which uses the information obtained from light quadratures to reconstruct a 3d image of the Wigner function. Light quadratures can be obtained by means of balanced homodyne detection (BHD). BHD uses a controlled interference between the quantum field to be characterized and a local oscillator, which is a coherent source with well-defined frequency and phase. The main feature of a BHD is its ability to measure extremely small noise signals, even below the quantum vacuum limit for squezeed light. To obtain precise measurements in BHD it is necessary to characterize the noise sources in the electronics of the BHD such as Johnson noise and fundamental noises such as shot noise. To characterize the noise in the BHD, time based and frequency-based measurements were performed to find the quantum to classical noise ratio (QCNR). QCNR measures the capacity of the BHD to distinguish quantum noise. A high QCNR allows us to make reliable measurements of the light quadratures. For this project we developed a circuit based on the one presented by Lang et al. in low noise balanced homodyne detector for quantum noise measurements.

This thesis reports the realization and applications of a versatile wideband balanced homodyne detector operating in the time domain and intended for Quantum Optical Tomography. The detector can work with high repetition rate lasers used for the production and measurement of the electric field quadratures of quantum states of light. Full characterization of the detector by shot-noise measurements and by verifying its capability to reconstruct the density matrix and Wigner function of various states of interest is given. By overcoming photodiodes response mismatch, high frequency electronics issues and by choosing an appropriate optical set-up, a high level of common mode suppression (52.4dB) and a low electronic noise gave a shot-to-electronic noise ratio of I3dB for a Local Oscillator with 6.2 x 108 photons-per-pulse on a ~ 100MHz bandwidth. Results for the characterization of a single-photon Fock state are presented. An average efficiency of 56% was obtained for the generation/detection of the state.

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.

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.

Here we report on the design, construction and characterization of a time domain Balanced Homodyne Detection apparatus operating in the regime of high electronic noise. The experimental setup has been commissioned by studying coherent ultrashort ( ∼ 80 fs) light pulses using Pattern-function Quantum Tomography. Furthermore, we proved that the electronic noise can be treated as a detector inefficiency showing the effectiveness of this approach by measuring light coherent states with different energies. In Quantum Mechanics the measurement of the state of a physical system implies to estimate the expectation value of any observable of the system. For a generic operator the expectation value is obtained starting from the measurement of an ensemble of observables defined “quorum ” 1. In particular, for the electromagnetic field the quorum is a continuum set of the field quadra-tures2,3. Balanced Homodyne Detection (BHD) is an experimen-tal method for measuring a discrete set of the field

Balanced homodyne detector (BHD) that can measure the field quadratures of coherent states has been widely used in a range of quantum information technologies. Generally, the BHD tends to suffer from narrow bands and an expanding bandwidth behavior usually traps into a compromise with the gain, electronic noise, and quantum to classical noise ratio, etc. In this paper, we design and construct a wideband BHD based on radio frequency and integrated circuit technology. Our BHD shows bandwidth behavior up to 1.2 GHz and its quantum to classical noise ratio is around 18 dB. Simultaneously, the BHD has a linear performance with a gain of 4.86 k and its common mode rejection ratio has also been tested as 57.9 dB. With this BHD, the secret key rate of continuous-variable quantum key distribution system has a potential to achieve 66.55 Mb/s and 2.87 Mb/s, respectively, at the transmission distance of 10 and 45 km. Besides, with this BHD, the generation rate of quantum random number generator could reach up to 6.53 Gb/s.