Coherence properties and cutoff wavelength determination in dielectric waveguides

In the field of optical communications and integrated optics, it would be worthwhile to have an experimental technique allowing a sensitive and precise determination of the cutoff wavelength in dielectric waveguides of various form, size, and length. In this paper we show how evaluation of the coherence properties of the EM field on a cross section of a generic dielectric waveguide is a precise technique suitable for this purpose. We also apply the method to determine the cutoff wavelength of an optical fiber in various experimental conditions and present the results.