Optical fiber index profiles by the refracted-ray method (refracted near-field scanning)

Abstract

This paper has two primary purposes. First, it provides an elementary description and tutorial overview of the refracted-ray method of measuring fiber index profiles. Second, it presents new results concerning the theoretical foundation, the linearity and precision, and other aspects of the method. In particular, we find that index differences may be measured to 5% or better and conclude by showing ~3% agreement with another laboratory and good agreement with numerical aperture measurements performed by participants in an interlaboratory comparison.

Application of the Refracted Near-Field Technique to Multimode Planar and Channel Waveguides in Glass

“…The problem of linearity between the measured RNF signal and the refractive index at the focal point has been discussed previously, but only in a qualitative manner [6,9]. Moreover, in our opinion the analysis given in [9] is not completely exact, as it does not take into consideration that the angular intensity distribution is not the same for the incoming and outcoming light cones.…”

Polarization-Transmission Channels in Monomode High Birefringent Optical Fibers

“…To the standard set-up [4,5] several units were added. To the standard set-up [4,5] several units were added.…”

Two-dimensional scanning focused refractive-index microscopy and applications to refractive-index profiling of optical fibers

“…12,13 Although these methods are nondestructive, 8,11 they are only suitable for circularly symmetric optical fibers. The latter category mainly contains the transmitted near-field (TNF) method, 14-18 the refracted near-field (RNF) method, 9,[19][20][21][22] and the reflectance measurement (RM) method. [23][24][25] This kind of methods can obtain the two-dimensional (2-D) RIP of both symmetric and asymmetric optical fibers through measuring the end faces.…”