Suppression of level fluctuation without extinction ratio degradation based on output saturation in higher order optical parametric interaction in fiber

Optical limiting operation based on output saturation in higher order parametric interaction in dispersion-shifted fiber is reported. The output powers in a parametric amplifier configuration were measured as a function of the signal input power, with the result that new-wavelength light is efficiently generated in addition to the pump, signal, and idler, resulting from a higher order parametric process, and its output power initially increases quadratically and then saturates as the input power increases. By utilizing this output property of the higher order parametric light, suppression of level fluctuation with an improved extinction ratio was demonstrated.