  Single-section quantum dash semiconductor lasers have attracted much
attention as an integrated and simple platform for the generation of THz-wide
and flat optical frequency combs in the telecom C-band. In this work, we
present an experimental method allowing to increase the spectral width of the
laser comb by the injection of a broadband optical noise from an external
semiconductor optical amplifier that is spectrally overlapped with the quantum
dash laser comb. The noise injection induces an amplification of the side modes
of the laser comb which acquire a fixed phase relationship with the central
modes of the comb. We demonstrate a broadening of the laser comb by a factor of
two via this technique.
