Dynamical characteristics of a monolithically integrated semiconductor laser have been experimentally studied. The laser consists of a distributed feedback semiconductor laser section, a phase controlling section and a semiconductor optical amplifier section. Using a general analysis method of dynamics, we have experimentally investigated the bifurcation route to chaos and the dynamical characteristics of intermittent chaos through the optical spectra, time series, phase portraits and power spectra of the laser. The results show that, under suitable operating parameters, the monolithically integrated semiconductor laser can be driven into intermittent chaos oscillation characterized by the chaotic state stochastically interrupted by the stable state. For fixing the currents of distributed feedback semiconductor laser section and semiconductor optical amplifier section and gradually increasing the current of the phase controlling section IP, the monolithically integrated semiconductor laser successively undergoes stable state, period one, intermittent chaos, and returns to stable state. The range of IP required for achieving intermittent chaos oscillation is determined. Moreover, the evolution of the average laminar time with the increase of IP has been analyzed, and the result shows that, with the increase of IP, the average laminar time decreases firstly, after reaches a minimum, and then rapidly rises.