Simulation Study On The Nonlinear Dynamic Behaviors Of Vertical Cavity Surface Emitting Laser

Vertical cavity surface emitting laser (VCSEL) will be the ideal light source for optical communications, optical interconnects, optical computations and optical signal processing due to its special structure and excellent features such as circular beams, low divergence angles that can coupled with fiber convenient; surface-emitting easy to integrate high density 2D arrays; single longitude mode operation due to its short cavity length.Different from the traditional numerical calculation method, the model of the vertical cavity surface emitting laser was established by SIMULINK based on the rate equations, and the influence of the typical structure parameters and spontaneous emission factor and gain compress factor on the high frequency and large signal modulation response was investigated. The stable operation condition was determined theoretically, and the dependent relations of these parameter with the period-doubling position, period-quadrupling position and chaos region were investigated, the condition of chaos occur was discussed as well. The simulation result indicated three methods to enhance the stability of VCSEL, they are minimizing the aperture of VCSEL, decreasing the thickness of active region reasonably and enhancing the spontaneous emission factor, respectively.The model was extended to suit the condition of VCSEL with external cavity, and the influence of optical feedback on the VCSEL which with short external cavity or relatively long external cavity was investigated by simulation, respectively. The results indicate that the small variation of external cavity length (~1μm) will cause laser output power show periodic undulation whose period is equal to half of the optical wavelength. In the condition of short cavity, the feedback does not destabilize the CW operation of VCSEL, however, with relatively long external cavity (~1cm) the output power follow the path of chaotic, double-period to single period oscillation are observed within the periodic undulation. The similar phenomenon was observed with the increasing of external cavity reflectivity. Furthermore, the high frequency injection method was applied to control chaos and proved valid. These results will be useful for designing and optimizing device.