Pulse Generation from Gain-Switched Vertical Cavity Surface Emitting Laser at 1.5 µm

Optical pulses with duration below 60 ps were generated by gain-switching a Vertical Cavity Surface Emitting Laser (VCSEL) emitting at 1.53 µm. We used a radio frequency (RF) sinusoidal signal to modulate the device near threshold. Relaxation oscillations and pulse train generation were observed depending on the gain switching conditions. We have characterized the dependence of the pulse width and amplitude on the RF excitation frequency and amplitude for different bias currents. The optimal configuration of the current bias and RF modulating signal provided the shortest pulse duration of 57 ps at a frequency of 800 MHz.