Fig. 6. Chaotic output and statistics analysis for the CSHM laser.

a Output RF spectra at 22, 23, and 24 mA and noise spectrum of the test system. b Temporal output waveform and c corresponding autocorrelation function at 25.6 mA, inset: zoom-in view of ACF. d The correlation integral curve of C_D(ε) versus the radius of the ball ε in logarithmic scale, and e corresponding slope of the integral curve in (d). f Derived K₂-entropy from the integral curve. All the curves tend to converge to a common value about K₂ ≈ 2.9 ns⁻¹ as D→∞