Generation of nonclassical photon states using correlated photon pairs and linear feedforward

Universal optical amplification without nonlinearity

We propose and experimentally realize a new scheme for universal phase-insensitive optical amplification. The presented scheme relies only on linear optics and homodyne detection, thus circumventing the need for nonlinear interaction between a pump field and the signal field. The amplifier demonstrates near optimal quantum noise limited performance for a wide range of amplification factors.

Tunable squeezed-light generation from twin beams using an optical-phase feed-forward scheme

We analyze an optical-phase feed-forward scheme to produce a squeezed-light beam from intensity-correlated twin beams generated by nondegenerate parametric amplification. The quadrature measurement of the idler beam at the output of the parametric amplifier is linearly fed forward onto the output signal beam with an electro-optic phase modulator. The minimum available squeezing factor is shown to be 1/(2g - 1), where g is the parametric amplifier gain, and is equal to the nonclassical intensity-noise reduction factor of the original twin beams at the output of the parametric amplifier. By changing the frequency of the input signal beam, one can generate tunable squeezed light with this scheme for application in precision spectroscopy.