Date of Award

3-1998

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Electrical and Computer Engineering

First Advisor

James A. Lott, PhD

Abstract

This dissertation consists of an in-depth theoretical analysis of the optical impact of transverse index confinement on the lasing modes of microcavity surface emitting lasers. Two different variational techniques were employed to calculate the relevant optical laser parameters: (1) modal resonance, field profile, (2) confinement factor, and (3) threshold gain. Through a semianalytic field analysis, two new confinement related effects were discovered: (1) a polarization dependent change in mirror reflectance with aperture radius, and (2) a mode dependent blueshift. Through a numerical field analysis, the physical mechanisms governing diffraction were ascertained. These are: (1) the transverse confinement of the optical mode, the degree of tilt of the mode propagation vector away from normal to the mirror surfaces, and (2) the density of parasitic modes in the spectral vicinity of the lasing mode. Based on these results, a new semianalytic technique was derived for estimating diffraction loss via rigorous coupling to the parasitic modes. Finally, this model was combined with a gain model and a new mode density model to compute spontaneous emission rate, light verses current, threshold current, and spontaneous emission factors for a low threshold oxide-apertured device.

AFIT Designator

AFIT-DS-ENG-98-03

DTIC Accession Number

ADA344256

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