Optical Heterodyne Generation of High-Dimensional and Broadband White Chaos

White chaos with a colorless spectral bandwidth of 14 GHz contained within a range of 3 dB is experimentally generated by optical heterodyning of two external-cavity laser diodes. Experimental and numerical results show that the signatures of laser relaxation oscillation and external-cavity resonance (i.e., time delay signature), which are intrinsic to the laser dynamics are totally eliminated in the heterodyne-generated chaos. Correlation dimensional analysis shows that the generated chaos has a high dimensionality, being greater than 10. In addition, the effects on the heterodyne spectral bandwidth of variations in the optical feedback strength and frequency detuning of the lasers are studied experimentally and theoretically. Opportunities are identified for the deployment of white chaos.