Suppression of the closed-loop photocurrent fluctuation below the amplifier dark noise was observed in both a negative-feedback light-emitting diode and a laser diode. We apply the concept of an anticorrelation light state proposed by Masalov et al to analyze the anticorrelation effect between the measured photocurrent fluctuation and the amplifier dark noise, which successfully explains our experimental observations. Our theoretical analysis also yields the squeezed spectrum of the light intensity fluctuation in the loop and the correlation coefficient between the photocurrent and the amplifier noise.
