BEND LOSS OF SLAB AND FIBER MODES COMPUTED WITH DIFFRACTION THEORY

Radiation losses of optical waveguides that are bent into a circle can be computed in a number of ways. In this paper we show that the bending losses of fiber modes can be calculated with the help of Fraunhofer's diffraction theory and test the validity of the result by showing that it is in agreement with the known bend loss formulas of the slab waveguide and of the LP(01)-mode of the round step-index fiber. Like most efforts of this kind, the accuracy of our bend loss calculations is limited by the use of a scalar theory for approximating a vector problem and by additional mathematical approximations that are required to solve an integral.