Effects of extra low-frequency noise injection on microwave signals generated by a gain-switched semiconductor laser

Low-frequency upconverted noise (1/f laser intensity noise and the low-frequency noise of the driver source) has been identified as the dominant noise generation mechanism in microwave signals generated by a Fabry-Perot gain-switched semiconductor laser. An experimental investigation is carried out using extra low-frequency noise injection added to the drive signal. Results show the dependence of the broadband intensity noise level, formed by the overlapping of the upconverted noise sidebands present at each harmonic, on gain-switching input parameters