Beamwidth approximations for the fundamental mode in symmetric double-heterojunction lasers

The beamwidth for the fundamental TE0mode in symmetric DH lasers is approximated within 4 percent by analytical formulas covering wide ranges of cavity thickness and refractive index steps. By using a Gaussian approximation for near-field distributions, and numerically calculated beamwidth curves, we find a Gaussian beam-like expression for the beamwidth, over the range , where is the normalized guide thickness. In the nonGaussian region , the beamwidth is estimated by using a corrected Dumke-like asymptotic approximation.