Improvement of detection of weak aperiodic binary signals in a bistable optical system by vibrational resonance
The experimental and numerical evidence of improvement of detection of subthreshold aperiodic binary signals by the use of phenomenon of vibrational resonance in a bistable vertical cavity surface emitting laser (VCSEL) in the presence of a fixed level of noise is presented. It is shown that an additional periodic modulation with a period much shorter than a bit duration in the aperiodic input signal allows one to increase significantly a cross-correlation coefficient between the input and the output of a bistable system as well as substantially to decrease bit error rate. An experimental observation of a time lag between the input and the output of a bistable VCSEL due to effect of high-frequency modulation is shown. The effect of asymmetry of a bistable quasipotential on the detection is also studied. The numerial results are in a qualititative agreement with experimental ones.