A high-SNR resonant balanced photodetector with LC notch filter for the pulsed light

The pulsed squeezed state plays a pivotal role in quantum information processing and precision measurement. In the detection of the pulsed squeezed state, the high noise power at its repetition rate prevents the achievement of a high signal-to-noise ratio (SNR). Therefore, a high-SNR detector that can suppress the high noise power of the repetition rate of pulsed light is very crucial. In this paper, we present a high-SNR resonant balanced photodetector that filters out the noise power of the repetition rate by introducing an LC series notch filter. A 24.37 dB attenuation is obtained at the 80 MHz repetition rate by finely adjusting the capacitance of the LC series notch filter. Consequently, the photodetector's maximum SNR is improved to 19.60 dB, which is 5 dB higher than previous studies. Our work provides a key detection tool for the measurement of the pulsed squeezed state.