Fig. 3: Generation and characterization of single-mode squeezed vacuum (SMSV).

a The dual-pump source is derived from a filtered, electro-optically modulated continuous-wave (CW) master laser and used to pump a photonic crystal ring resonator (PhCR), generating single-mode quadrature squeezing via dual-pump spontaneous four-wave mixing. The generated SMSV is detected by a balanced homodyne detector (BHD) and analyzed using an electronic spectrum analyzer (ESA). EOM electro-optic modulator, EDFA erbium-doped fiber amplifier, PF programmable filter, VBG volume Bragg grating filter, FC fiber collimator, PD photodetector, OSC oscilloscope, OSA optical spectrum analyzer. b Measured shot-noise normalized quadrature variance of the SMSV at 27 mW of total pump power and 20 MHz sideband frequency. c Measured squeezing and antisqueezing at 20 MHz sideband frequency as a function of total on-chip pump power. Error bars indicate the 1σ confidence intervals. d Measured squeezing spectrum (corrected for the BHD efficiency and dark noise clearance) at 33 mW of total pump power and simulated squeezing spectrum. All data is taken at 2 MHz resolution bandwidth and 100 Hz video bandwidth.