Beltrami, DLove, JohnLadouceur, Francois2015-12-130306-8919http://hdl.handle.net/1885/93473We derive simple analytical expressions, using geometric optics, to describe the power output characteristics of various multimode devices, including acute angle X-junctions, symmetric Y-junctions and multimode interference couplers. The ray-tracing results compare well with results obtained using a finite difference beam propagation method solution of the governing scalar wave equation.Keywords: Fiber optics; Finite difference method; Optical devices; Optical fiber coupling; Ray tracing; Wave equations; Multimode planar devices; Multimode fibers199910.1023/A:10069711088062015-12-12