An efficient decomposition of the diffraction pattern from optical dis
ks that yields insight into the origin and the characteristics of vari
ous signals is described. The Babinet principle is used to separate co
mponents that describe the data signal, servo signals, and three types
of cross talk. The construction of a basis set that yields efficient
calculation for optimization studies is described. Two media types are
considered as examples. Several applications are also described, incl
uding an explanation for the origin of the differential phase-detectio
n tracking signal that is used with DVD-ROM media. (C) 1998 Optical So
ciety of America.