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A low-noise, high-SNR balanced homodyne detector for the bright squeezed state measurement in 1–100 kHz range*

Authors :
Yaohui Zheng
Qingwei Wang
Jinrong Wang
Jing Su
Long Tian
Source :
Chinese Physics B. 29:034205
Publication Year :
2020
Publisher :
IOP Publishing, 2020.

Abstract

We report a low-noise, high-signal-to-noise-ratio (SNR) balanced homodyne detector based on the standard transimpedance amplifier circuit and the inductance and capacitance combination for the measurement of the bright squeezed state in the range from 1 kHz to 100 kHz. A capacitance is mounted at the input end of the AC branch to prevent the DC photocurrent from entering the AC branch and avoid AC branch saturation. By adding a switch at the DC branch, the DC branch can be flexibly turned on and off on different occasions. When the switch is on, the DC output provides a monitor signal for laser beam alignment. When the switch is off, the electronic noise of the AC branch is greatly reduced at audio-frequency band due to immunity to the impedance of the DC branch, hence the SNR of the AC branch is significantly improved. As a result, the electronic noise of the AC branch is close to −125 dBm, and the maximum SNR of the AC branch is 48 dB with the incident power of 8 mW in the range from 1 kHz to 100 kHz. The developed photodetector paves a path for measuring the bright squeezed state at audio-frequency band.

Details

ISSN :
16741056
Volume :
29
Database :
OpenAIRE
Journal :
Chinese Physics B
Accession number :
edsair.doi...........b6b900987898e3aa72405e6bb54eb6ce