Enhancement of Chaos Bandwidth in VCSELs Induced by Simultaneous Orthogonal Optical Injection and Optical Feedback

In this paper, we present an experimental study of bandwidths of broadband chaotic signals in a single-mode vertical-cavity surface-emitting laser (VCSEL) subject to orthogonal optical injection and optical feedback simultaneously. Bandwidths of the two linear polarizations and total power are measured for different values of frequency detuning and bias currents. When the VCSEL is subject to optical feedback only, both linear polarizations of the VCSEL are excited showing chaotic dynamics. Under simultaneous optical feedback and optical injection for small bias currents, we demonstrate that the orthogonal polarization can give a much larger value of the chaotic bandwidth than the total emitted power in agreement with Perez et al.