Wideband chaos generation based on a dual-mode microsquare laser with optical feedback

We propose and demonstrate the generation of wideband chaos based on a dual-mode microsquare semiconductor laser with optical feedback. By adjusting the dual-mode intensity ratio and the feedback strength, wideband chaos covering more than 50 GHz in the RF spectrum is achieved. The standard and effective bandwidths of the chaotic signal are 31.3 GHz and 30.7 GHz with the flatness of 8.3 dB and 6.1 dB, respectively.