Inhomogeneities in monomode optical waveguides

Power is radiated from any imperfection in an optical dielectric rod transmission line, causing signal loss and crosstalk. On the other hand power can be fed into optical waveguides only at discontinuities. A survey is given on the radiation and transmission properties of six inhomogeneities in single mode optical waveguides: a free end, a gap, an axes offset, a step in diameter, a corner and a bend. Each problem is illustrated by a picture of the electromagnetic field showing constant amplitude and constant phase contours which have been measured using microwave models. Comments are given an the theoretical methods used to analyze the discontinuities and some results of the analysis are mentioned.