Low-frequency low-noise balanced homodyne detector

Abstract

The invention relates to the field of squeezed state optical field quantum noise measurement. A low-frequency low-noise balanced homodyne detector includes a differential circuit composed of two photodiodes, a bootstrapping current-voltage conversion circuit composed of two bumpers and a trans-impedance operation amplifier (5), and an AC and a DC output circuit composed of a first capacitor (6) and a first resistor (7) separately. According to the invention, through quantitative analysis of input current total noise of the low-frequency low-noise balanced homodyne detector in a low frequency band and since a sampling resistor in a traditional detector is removed and the bootstrapping current-voltage converter is adopted, the electronic noise of the low-frequency low-noise balanced homodynedetector within a frequency of 20 Hz to 200kHz is reduced substantially and requirements for high gain, high common-mode rejection ratio, simple structure and low cost are met.

Description

technical field [0001] The invention relates to the field of measuring quantum noise of squeezed light field. Background technique [0002] Due to the advantages of effectively reducing classical noise, amplifying signal light and directly characterizing the fluctuation of the quadrature component of signal light, the balanced zero-beat detection method has become one of the best methods for measuring the degree of compression of squeezed states in quantum information science research. However, the electronic noise, gain and common-mode rejection ratio of the detector are the main factors that limit the measurement of quantum noise by the balanced zero-beat detection method. In order to reduce the impact of electronic noise on the measurement, the electronic noise measured by the photodetector should be at least 10dB lower than the shot noise benchmark. [0003] At present, the generation and measurement of squeezed light are mostly concentrated in the radio frequency range...

AI Technical Summary

Problems solved by technology

[0003] At present, the generation and measurement of squeezed light are mostly concentrated in the radio frequency range (~ MHz), because the classical noise of light in the radio frequency band is relatively small, and the system noise is easy to reach the limit of quantum noise, which is easy to measure. In the gravitational wave detection In experiments such as Michelson interferometer or weak magnetic field detection, the detection frequency is generally in the low frequency range (20Hz-20kHz). Due to limitations and imperfections in circuit design, it is impossible to meet the requirements of direct measurement.

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