A theoretical approach is used to investigate the coupling of surface plasmon-coupled emission to Fabry-Perot resonance in the sample layer. Quantities investigated are emission angles, polarization, power levels, and fluorescence lifetimes. The results are compared to experimental findings. For comparison a layered structure without surface plasmons, possessing only dielectric Fabry-Perot resonances, is explored. This structure seems to be amenable to s-polarization only but is in principle loss-less and has more degrees of freedom for design and optimization.