Picosecond pulse generation (<1.8 ps) in a quantum well laser by a gain switching method

A picosecond pulse (<1.8 ps) at 8570 Å is successfully generated by a gain switching method in an optically pumped GaAs/AlGaAs multiquantum well laser with a cavity length of 155 μm. This is the narrowest pulse width so far achieved in semiconductor lasers without the external cavity. We believe that this short pulse generation results from the enhanced differential gain due to the two-dimensional properties of the carriers in the quantum wells.