"This thesis is devoted to the experimental study of stochastic effects in multistable semiconductor and solid-state lasers. In the first part, the experimental observation of coherence enhancement of noise-induced intermittency in a semiconductor laser subject to optical injection from another laser at the boundary of the frequencylocking regime is presented. The experimental interspike-interval fluctuations were used to quantitatively characterize the intermittent behavior. In the second part, we study noise-induced intermittency in two mutually coupled semiconductor lasers. Gaussian white noise was applied when both lasers operated in the low-frequency fluctuations regime, near their lasing threshold. The intermittent behaviour of the system output was found, and the type of intermittency analyzed with time series and power spectra. In the third part, we study the dynamics of a dual-cavity Nd:YAG laser with second harmonic generation in one of the cavities and loss modulation in another cavity. We found coexistence of attractors and different dynamical regimes as the frequency of the harmonic modulation of the infrared light was varied."