Analysis of mode-field radius calculated from far-field radiation patterns

The mode-field radius (MFR) is an important property of single-mode fibers since it is related to splice loss and dispersion. Anderson and Philen1 have shown that measurements of the MFR using the transverse offset, far field with Gaussian approximation, and far field with Hankel transformation all agree for step-index fibers at a wavelength of 1.3 µm provided the Gaussian fit to the far-field data is selected by maximizing an overlap integral. Anderson2 and Samson3 have shown that this is also true for mode distributions markedly different from Gaussian.