Patent ID: 8311410

Claim:
An optical switch, comprising: a first polarization controller to control a polarization direction of a phase-modulated optical signal or a frequency-modulated optical signal; a nonlinear optical medium to which the optical signal output from said first polarization controller is input; an optical pulse generator to generate a control pulse with a wavelength different from that of the optical signal and to provide the control pulse to said nonlinear optical medium; a second polarization controller, placed between said optical pulse generator and said nonlinear optical medium, to align a polarization direction of the control pulse to a designated angle relative to the polarization direction of the optical signal; and a polarizer, placed at the output side of said nonlinear optical medium, having a main polarization axis orthogonal to a polarization direction of the optical signal output from said nonlinear optical medium, the optical signal being selectively amplified with parametric amplification by the control pulse around a polarization direction of the control pulse in said nonlinear optical medium, an angle between the polarization direction of the optical signal and the polarization direction of the control pulse being between 40 and 50 degrees.