高周波変調にもとづくAlGaAs半導体レーザーからの超短光パルス発生

抄録

DH AlGaAs lasers with relatively low DC bias under the oscillation threshold superposed by high RF modulation were demonstrated to be quite feasible for the generation of a train of about 30 ps optical pulses at a modulated frequency of sub GHz range. The pulse width was measured by an SHG correlation method as well as an ultrafast streak camera, and both the results agreed fairly well.
To explain the generation mechanism of these ultrashort optical pulses in a highly modulated semiconductor laser, the rate equation analysis was performed and the results were generally in good agreement with the experimental ones. Furthermore by analyzing the SHG correlation traces by a computer simulation, it was inferred that the individual ultrashort optical pulses obtained have internal substructures of periodic noises, whose spike widths were of an order of subpicoseconds, due to the randomness of phases among lasing modes.