J. Arnaud

Optical and Quatum Electronics, 18, 335-346, mai 1986

ABSTRACT

The natural linewidth of lasers is shown to be enhanced with respect to the value predicted by the Schawlow-Townes formula whan the gain is high and inhomogeneous in transverse or longitudinal directions. A general formula for the linewidth enhancement is derived from first principles : Maxwell’s equations and the fluctuation-dissipation theorem, for media with arbitrary bi-anisotropy and dispersion. The result is expressed in terms of an integral of the resonating fiels over the cavity volume. For isotropic media (scalar ε and μ), thos formula generalizes previous results by Petremann for gain-guided lasers, by Ujihara for lasers with low reflectivity mirrors, and results obtained by others authors for lasers coupled to long external cavities. The role of non-reciprocity is discussed.

LIEN VERS  L’ARTICLE : NATURAL LINEWIDTH OF ANIOTROPIC LASERS