Tolerancing and corner cases in optical simulation

Our work discusses the tolerance modeling of an optical fiber that is inserted into a cylindrical alignment bore. We note that some commercial optical simulation software suites have the mechanical tolerance operands entered in Cartesian coordinates and if radial variation is entered as simple X and Y de-centering, there arises a kind of "corner condition" where fiber in the opto-mechanical model is offset more than is possible in the physical implementation resulting in an overly-conservative estimate of the worst-case coupling efficiency. Approaches to avoid this over estimation are presented and discussed.