POLARIZATION-MODE DYNAMICS IN STRAINED 1.3 MU-M INGAASP INP LASERS UNDER PICOSECOND CURRENT MODULATION/

The dynamic behaviour of the TE and TM polarized output from ridge-wav eguide InGaAsP/InP lasers which are electrically pumped with 300 ps pu lses is studied experimentally and theoretically. For the first time, different polarization characteristics depending on the amplitude of t he current pulse and the level of the de bias are reported. While stro ng mode competition resulting in TE or TM mode emission in separate cu rrent intervals is found in the cw regime, simultaneous lasing of both modes, transients between TE and TM in the ps range as well as common GHz relaxation oscillations of TE and TM emission are observed under pulsed excitation. TE and TM pulses shorter than 40 ps are measured. T he laser dynamics is modelled through space-dependent rate equations. Numerical results suggest, that the fast polarization switching is due to a lateral shift of the TE and TM modes against each other.