An organic light emitting device, including a substrate, a conductive nitride electrode, an organic film, and a second conductive electrode. The present invention particularly relates to those servo recordings which were written with a uni-polar current waveform. The body is used as a conductor for communication between the first and the second parts. The shape of the shaped surface may be adjusted, if necessary, by replacing the rib boards with boards of a different shape. Furthermore, adjustment of the group delay can readily be achieved, in units of a fraction of a micro-second, providing the ability to fine tune the group delay for feed forward applications.