Lateral transverse mode instability and its stabilization in stripe geometry injection lasers

A numerical analysis has been carried out on the behavior of semiconductor injection lasers with a stripe geometry double-heterostructure, taking into account spatial hole-burning and its effect on the waveguiding. It is shown that spatial hole-burning, the negative dependence of refractive index
eta
on the excited carrier density
n (d_{eta}/ dn < 0)
, and the lack of complete symmetry in any real laser structure are the three critical factors responsible for the lateral mode instability leading to such anomalous behaviors these lasers exhibit as a "kink" in the light output versus current relation and the lateral shift in the emission spot. Effects of rigid refractive index and gain-loss profiles built into the laser crystal on the mode stability have been examined, and conditions for kink-free, single lateral mode oscillations have been investigated.