Rise Time and Gain Fluctuations of an Electrooptical Amplified Switch Based on Multipulse Injection in Semiconductor Optical Amplifiers

Subnanosecond electrooptical switching times with 26-dB extinction ratio were obtained by using semiconductor optical amplifiers driven by a multipulse injection current. The multipulse switching current was generated by superimposing fast electronic pulse signals in a microwave resistive combiner. Although very fast switching is achievable, nonlinear behavior and circuits parasitic induce gain fluctuations and overshooting during the off-on process. Theoretical and experimental results show that the reduction of parasitics is an important parameter for improving the switching performance. The multipulse injection technique can improve the switching speed for a chosen degree of overshoot.