Two light emitting diode (LED) structures such as the introducing of AlGaN confining layer and the embedded photonic crystal (PC) LED are proposed to improve the light extraction efficiency of PC LEDs. The distributions of guided modes propagated in LED are analyzed, and the modal extraction lengths are calculated using high-resolution angle-resolved measurements in order to research the interaction of each guided mode with PCs. The impact of structure parameters design on modal extraction length is considered. The result shows that the introduction of an AlGaN confining layer in LEDs is effective in extracting a fraction of the optical energy of low order modes, but this approach is limited by the growth of the lattice mismatched AlGaN layer on GaN. And embedded PC LEDs have superior extraction of the guided light due to spatially overlapped with all guide modes which have the higher interaction between all optical modes.