Coherence resonance in an optical system

Summary form only given. Recently, Pikovsky and Kurts studied the effect of noise in fluctuations of the time between successive excitable pulses are minimized for a well-defined amount of the input noise. They named such a behavior coherence resonance. We present an experimental investigation of the effects of noise in an excitable optical system, namely, a semiconductor laser with optical feedback. Changing the amount of noise, and choosing the adequate indicators, we report experimental evidence of coherence resonance.