Beamwidth for asymmetric and multilayer semiconductor laser structures

An expression for the far field of the fundamental mode perpendicular to the active layer in an asymmetrical dielectric slab waveguide is derived. Using normalized waveguide parameters, universal plots of the beamwidth are presented. These plots take in the obliquity factor correction. A comparison is made between experimental results for symmetrical GaInAsP lasers at wavelengths near 1.3 microns and theoretical predictions by Buus and Adams (1979). Calculated results for the 1.55 micron wavelength are given. A numerical method for the calculation of the far field for structures in which four or more layers must be included is outlined.