Abstract

Techniques for predicting the mode shape of stable resonators as a function of gain, such as the Fox-Li iterative method, can encounter difficulty in multitransverse-mode lasers because of the effects introduced by employing coherent combination of the individual modes. We have developed an alternative approach that assumes incoherent mode combination. The modes of the bare cavity or of a "gain-weighted" cavity are identified first. Then an iterative technique is applied to establish the mode amplitudes for self-consistent round-trip propagation in the laser. The specific characteristics of the gain media exert a strong influence on the numbers of transverse modes that lase.

© 1990 Optical Society of America