This work presents the experimental measurement of the extraction lengths of individual guided modes of embedded photonic-crystal (PhC) light-emitting diodes (LEDs), which corroborates its superior guided light extraction compared to surface PhC LEDs. While in surface PhC LEDs a number of low order modes were not observed experimentally, in embedded PhC LEDs, the stronger interaction of all guided modes with the PhCs resulted in the diffraction of all low order modes with short extraction lengths, ranging from 60 to 80 mu m. (C) 2010 The Japan Society of Applied Physics