Chaos generation by a hybrid integrated chaotic semiconductor laser

We design a hybrid integrated chaotic semiconductor laser with short-cavity optical feedback. It can be assembled in a commercial butterfly shell with just three micro-lenses. One of them is coated by a transflective film to provide the optical feedback for chaos generation while insuring regular laser transmission. We prove the feasibility of the chaos generation in this compact structure and provide critical external parameters for the fabrication by theoretical simulations. Rather than the usual changeless internal parameters used in previous simulation research, we extract the real parameters of the chip by experiment. Moreover, the maps of the largest Lyapunov exponent with varying bias current and feedback intensity K_ap demonstrate the dynamic characteristics under different external-cavity conditions. Each laser chip has its own optimal external cavity length (L) and feedback intensity (K_ap) to generate chaos because of the different internal parameters. We have acquired two ranges of optimal parameters (L=4 mm, 0.12 < K_ap < 0.2 and L=5 mm, 0.07 < K_ap < 0.12) for two different chips.