Mode transformation in VCSEL emitting pseudorandom sequence of pulses

The dynamics of vertical cavity surface emitting laser (VCSEL) operation was numerically simulated under the pumping current modulation by pseudorandom pulsed sequence for the NRZ encoding format. It was obtained that, for certain laser parameters and modulation ones, the emitted pulses have substantially differing mode composition due to delay in exciting the side modes with respect to the main mode excitation. We consider this result to be of importance for applications and to be taken into account with the VCSEL's use in modern optical-fibre based telecommunication systems.