Observation of a short optical pulse (<1.3 ps) from a gain-switched quantum well laser

Short light pulse generation from an optically pumped GaAs/AlGaAs quantum well laser is measured. The shortest pulse width achieved so far is less than 1.3 ps. In addition, it is found that the pulse from varies randomly even when the same excitation condition, which results from stochastic behavior of the spontaneous emission coupling to the lasing mode. In order to discuss these results in more detail, spatial dependent rate equations are analyzed in which the stochastic process of the spontaneous emission and the traveling effect of spontaneously generated optical wave packets are included.