Rubidium resonant squeezed light from a diode-pumped optical parametric oscillator

We present the quadrature and polarization squeezing generated by a sub-threshold optical parametric oscillator (OPO) resonant to rubidium D1 line and pumped by a frequency-doubled diode laser. We demonstrate here a technique to eliminate the effects of laser phase noise on quadrature squeezing. The technique uses cavity stabilization of the laser frequency, in combination with a carefully chosen delay between the squeezed light and the local oscillator beam. By introducing fiber delay lines into the local oscillator path the group delay between squeezing path and local oscillator path can be matched so that phase fluctuations of the primary laser are canceled out in white-light configuration.