Influence of output optical losses on the dynamic characteristics of 1.55-$\mu$m wafer-fused vertical-cavity surface-emitting lasers

The results of studying the dynamic characteristics of 1.55-$\mu$m single-mode vertical-cavity surface-emitting lasers (VCSELs) formed by the fusion of wafers of high-quality Bragg reflectors and an active region based on thin highly strained InGaAs/InAlGaAs quantum wells are presented. It is found that the proposed design of the active region and optical microcavity of the laser make it possible in principle to attain a high level of differential laser gain in the temperature range of 20$^{\circ}$C–85$^{\circ}$C, but weak electron localization leads to an increase in gain compression at elevated temperatures. Due to this fact, the VCSEL modulation bandwidth at 20$^{\circ}$C can be increased from 9.2 to 11.5 GHz due to an increase in output optical losses, while the modulation bandwidth at 85$^{\circ}$C does not exceed 8.5 GHz, depends weakly on the output optical losses, and is mainly limited by the optical-gain saturation.