UNIVERSAL NOISE RISE IN A PARAMETRIC MAGNETOSTRICTIVE AMPLIFIER

Noise rise in the high-gain limit of a parametric magnetostrictive amplifier is observed to occur close to the bifurcation point of the unperturbed strain dynamics. This work presents the first quantitative agreement between experimental results and the predicted universal scaling laws which relate the signal and noise gain to the bifurcation parameter. We also observe a scaling law, not predicted by the theory, in which the point of maximum signal gain shifts away from the bifurcation point as a function of the detuning with a critical exponent equal to -0.33 +/- 0.04.