Fig. 1. Experimental setup of broadband chaos generation in VCSEL with optical feedback

Fig. 2. Characteristics of free-running VCSEL. (a) Variation of VCSEL output power with bias current; (b) spectrua of VCSEL at a bias current of 18 mA

Fig. 3. Dynamics paths and state distributions of VCSEL entering chaos. (a)‒(c) Time series and phase diagrams of steady state, quasiperiodic state, and chaotic state; (d)‒(f) state parameter regions of X+Y mode, X mode, and Y mode

Fig. 4. Typical chaotic output characteristics of VCSEL under a bias current I=18 mA and a feedback strength K_f =30%. (a) Spectra; (b) frequency spectra

Fig. 5. Effects of feedback strength and bias current on chaos bandwidth of VCSEL. (a) Chaos bandwidth as a function of bias current at a fixed feedback strength of K_f=30%; (b) chaos bandwidth as a function of feedback strength at a fixed bias current of I=18 mA

Fig. 6. Maps of chaos bandwidth as a function of feedback strength and bias current. (a) X+Y mode; (b) X mode; (c) Y mode

Fig. 7. Typical chaotic output autocorrelation functions of the VCSEL under bias current I=18 mA and feedback strength K_f =30%. (a) X+Y mode and X mode; (b) Y mode

Fig. 8. Effects of feedback strength and bias current on chaos TDS of VCSEL. (a) Chaos TDS as a function of bias current at a fixed feedback strength of K_f=30%; (b) chaos TDS as a function of feedback strength at a fixed bias current of I=18 mA

Fig. 9. Maps of chaos TDS as a function of feedback strength and bias current. (a) X+Y mode; (b) X mode; (c) Y mode