Influence of thermal processes on the threshold characteristics of a heterojunction laser with spatially inhomogeneous injection

It was found that the lasing threshold of a two-section injection heterolaser can be reduced if the temperature of the strongly injected section is higher than that of the weakly injected one. This was due to an increase in the total optical gain because the spectral maxima of the gain of the separate sections were brought closer together. Consequently, the cw lasing threshold was less than the value for the pulsed operation. Moreover, in a certain range of injection currents under pulsed pumping conditions the onset of lasing was delayed relative to the leading edge of a current pulse by a time up to 1 msec and this time was determined by the dynamics of the temperature distribution in the laser crystal.