ELECTROMAGNETIC THEORY OF DISTRIBUTED FEEDBACK LASERS IN PERIODIC DIELECTRIC WAVEGUIDES

摘要

A theory for distributed feedback lasers in transversely bounded structures is developed. The space harmonics approach is used to discuss the general properties of periodic structures. The coupled mode approach is used to develop expressions for the threshold gain, longitudinal mode structure, and electromagnetic field distribution for distributed feedback lasers. Three basic structures are considered for distributed feedback lasers--thin film waveguides, diffusion waveguides, and fiber waveguides. Equations for the amplification of a waveguide mode that extends transversely over both regions20.with and without gain are derived. Analytical expressions are derived for coupling between modes in periodically perturbed dielectric waveguides. Sinusoidal perturbations of the electric permittivity and of the waveguide boundary are considered.