Advances in the finite difference beam propagation method

In this paper we describe some advances in the finite difference beam propagation method (FD-BPM) whilst noting that we also pioneered the development of a number of very powerful semianalytical methods (F-OPT, FSRM, HSRM, SI methods), which are ideally suited to CAD software and for linking with FD-BPM to exploit the flexibility of the former and the speed of the latter. Some of the current issues are reviewed: full-vectorial and wide-angled implementations, improved discretization schemes, the perfectly matched layer boundary conditions, the use of non-standard coordinate systems, mode extraction via FD-BPM and bi-directional (reflective) FD-BPM.