Electromagnetic theory of distributed feedback lasers in periodic dielectric waveguides

coupled mode theory;DFB;distributed feedback lasers;fiber lasers;gratings;optical gain;optical waveguides;semiconductor lasers

Evans, Gary A. ; Papas, Charles Herach

University:California Institute of Technology

Department:Engineering and Applied Science

关键词: coupled mode theory;    DFB;    distributed feedback lasers;    fiber lasers;    gratings;    optical gain;    optical waveguides;    semiconductor lasers;   

Others  :  https://thesis.library.caltech.edu/4799/1/Evans_ga_1975.pdf

美国|英语

来源: Caltech THESIS

【 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 wave-guides.Equations for the amplification of a waveguide mode that extends transversely over both regions 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.Theoretical results indicate that an optimum design of distributed feedback lasers can be achieved by an appropriate choice of geometrical parameters. Regions of optimum design are illustrated in numerous plots of normalized threshold gain versus normalized laser frequency.