Fig. 4. Squeezing spectra and power sweep.

(A) Maximum (red) and minimum (blue) measured PSD spectrum (normalized by the shot noise, electronic noise subtracted) versus measurement frequency of the RFSA at the TEC temperature setting of 43.4°C with on-chip FH power of 20 mW going into the SHG section. Dotted lines represent the squeezing theory (see the Supplementary Materials). (B) Measured PSD values (normalized by shot noise, electronic noise subtracted) averaged from 58 to 60 MHz at around the peak (red) and dip (blue) of the LO phase shifter dc voltage sweep versus on-chip input FH power going into the SHG section. TEC temperature setting was at 43.4°C for this measurement. Dotted lines are theory lines (see the Supplementary Materials).