CALCULATION OF MODAL POWER TRANSFER IN TAPERED ASYMMETRIC SINGLE-MODECOUPLERS

We solve the coupled mode equations for the even and odd modes of an a symmetric tapered coupler by means of an accurate analytical approxima tion. Using this we calculate the taper-induced power transfer as a fu nction of asymmetry for constant taper angle and core width in slab ge ometry. We show that further simplifications can be made when the powe r transfer is either small or large.