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