GAIN LOSS CHARACTERIZATION OF OPTICAL WAVE-GUIDE AND SEMICONDUCTOR-LASER STRUCTURES/

Finite element analysis, employing the H-field vector and scalar formu lations, has been used with the aid of perturbation techniques to dete rmine the modal gain and loss characteristics of optical waveguides an d semiconductor laser structures. The accuracy and the applicability l imits of the perturbation method are examined, and compared to the mor e accurate but more computer intensive transverse magnetic field formu lation for an embedded-channel waveguide. Further, the method is appli ed to a rib-waveguide laser structure, where the imaginary part of the refractive index of the InGaAsP active layer is seen to vary accordin g to the carrier concentration profile. Finally, the accuracy of a wid ely used but simpler method for determining the modal gain for QW and MQW laser structures, in terms of the optical mode confinement, is det ermined.