Fig. 1. Schematic of the experiment setup. Laser, home-made Nd:YVO4 ring laser with 2.5 W continuous-wave single-frequency output power at the wavelength of 1064 nm; MC, mode cleaner; EOM, electro-optical modulator; FM, flip mirror; OPO, optical parametric oscillator; DBS, dichroic beam splitter; SHG, second harmonic generation; PZT, piezoelectric transducer; PD, photodetector; BHD, balanced homodyne detection.

Fig. 2. BHD scheme based on a JFET buffering input and another JFET bootstrap structure. HQED, high quantum efficiency photodiode from Laser Components.

Fig. 3. Shot noise limit measurement with ten different LO powers.

Fig. 4. Quantum noise levels of the squeezed and anti-squeezed state at the pump power of 133 mW as the LO phase is being scanned.