Experimental and numerical analysis on temporal dynamics of polarization switching in an injection-locked 1.55-μm wavelength VCSEL

We present experimental and numerical study of temporal characteristics of injection-locked polarization switching of a conventional-type 1.55-μm wavelength single-mode vertical cavity surface-emitting laser (VCSEL). Delayed recovery response of the main-mode of the VCSEL was observed when short and strong optical injection pulses of an orthogonal polarization to the VCSEL's main polarization-mode were applied. Numerical analysis based on a spin-flip model describes that the relatively long upper level lifetimes compared to a short injection-pulse width and long cavity photon lifetimes cause delayed recovery response of the main-mode of the VCSEL. An optimum bias current of the VCSEL was also observed for the shortest recovery time of its free-running polarization mode after the orthogonal polarization beam pulse injection.