| This thesis deals with several topics related to the lateral modes of edge-emitting semiconductor lasers. The first topic is the improvement of lateral beam quality for high power operation. A thermally controlled antiguiding unstable-resonator semiconductor laser with cleaved facets is proposed. With temperature controlled by monolithically integrated micro-heaters, the beam propagation factor is improved by 8 times at 300 mW and by 6 time at 600 mW. The second issue is monolithic semiconductor laser beam steering. Two new mechanisms, thermally controlled offset gain and index guiding lasers and fan laser arrays, have been proposed and demonstrated. They both have single-lobed Gaussian intensity distributions. The fan laser array has shown a total steering angle of 80{dollar}spcirc{dollar} with eleven resolvable spots, which surpasses the previous results by a factor of three. The third issue is the nonlinear interaction between the semiconductor gain medium and optical waves. The filamentation effect is studied with perturbation theory. Analytical spatial solitary waves have been obtained. The fourth issue is the complex Hermite-Gaussian functions and their applications. An analytical integral expression has been obtained. The generalized complex Gaussian duct is discussed. It is found that the biorthogonal mode expansion and adjoint mode coupling theory in unstable resonators need to be improved. The fifth issue is the lateral modes of stable resonator and stadium resonator semiconductor lasers which have been designed, fabricated and tested. For the stable cavity semiconductor lasers, three distinct operation regions are identified as the stable cavity region, the transition region, and the geometrically unstable region. Preliminary results on stadium resonator semiconductor lasers have also been obtained. |
