We describe an efficient decomposition of the diffraction pattern from optical disks that yields insight into the origin and characteristics of various signals. Babinet's Principle is used to separate components that describe the data signal, servo signals, and two types of crosstalk. The construction of a basis set is described that yields efficient calculation for optimization studies. Two media types are considered as examples. Several applications are also described, including an explanation for the origin of the differential phase detection tracking signal that is used with DVD-ROM media.