## Abstract

An efficient decomposition of the diffraction pattern from optical
disks that yields insight into the origin and the characteristics of
various signals is described. The Babinet principle is used to
separate components 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, including an explanation for the
origin of the differential phase-detection tracking signal that is used
with DVD-ROM media.

© 1998 Optical Society of America

Full Article |

PDF Article
### Equations (11)

Equations on this page are rendered with MathJax. Learn more.

(1)
$${U}_{T}=\sum _{i=1}^{i=N}{U}_{i},$$
(2)
$${\mathit{\u0168}}_{T}=\sum _{i=1}^{i=N}{\mathit{\u0168}}_{i},$$
(3)
$${U}_{T}={r}_{L}{U}_{F}+\left({r}_{M}-{r}_{L}\right)\left({U}_{M1}+{U}_{M2}\right),$$
(4)
$${\mathit{\u0168}}_{T}=\sum _{i=1}^{i=N}{c}_{i}{\mathit{\u0168}}_{i},$$
(5)
$${U}_{M1}=\sum _{j=1}^{j=L}{c}_{M1j}{u}_{M1j},$$
(6)
$${\tilde{I}}_{T}\propto |{\mathit{\u0168}}_{T}{|}^{2}=|{r}_{L}{|}^{2}\left[|{\mathit{\u0168}}_{F}{|}^{2}+|{\mathit{\u0168}}_{M1}{|}^{2}+2|{\mathit{\u0168}}_{F}{\mathit{\u0168}}_{M1}|cos\left(\mathrm{\Delta}{\mathrm{\varphi}}_{F1}\right)\right],$$
(7)
$${\tilde{I}}_{T}\propto |{\mathit{\u0168}}_{T}{|}^{2}=|{r}_{M}{|}^{2}\left[|{\mathit{\u0168}}_{M1}{|}^{2}+|{\mathit{\u0168}}_{M2}{|}^{2}+2|{\mathit{\u0168}}_{M1}{\mathit{\u0168}}_{M2}|cos\left(\mathrm{\Delta}{\mathrm{\varphi}}_{12}\right)\right],$$
(8)
$${\tilde{I}}_{T}\propto |{\mathit{\u0168}}_{T}{|}^{2}=|{r}_{L}{|}^{2}\left[|{\mathit{\u0168}}_{F}{|}^{2}+|{\mathit{\u0168}}_{M1}{|}^{2}+|{\mathit{\u0168}}_{M2}{|}^{2}+2|{\mathit{\u0168}}_{F}{\mathit{\u0168}}_{M1}|cos\left(\mathrm{\Delta}{\mathrm{\varphi}}_{F1}\right)\left(\mathrm{a}\right)+2|{\mathit{\u0168}}_{F}{\mathit{\u0168}}_{M2}|cos\left(\mathrm{\Delta}{\mathrm{\varphi}}_{F2}\right)\left(\mathrm{b}\right)+2|{\mathit{\u0168}}_{M1}{\mathit{\u0168}}_{M2}|cos\left(\mathrm{\Delta}{\mathrm{\varphi}}_{12}\right)\right].\left(\mathrm{c}\right)$$
(9)
$${i}_{\mathrm{DATA}}={i}_{1}+{i}_{2}+{i}_{3}+{i}_{4},$$
(10)
$${i}_{\mathrm{QPD}}={i}_{1}+{i}_{4}-{i}_{2}-{i}_{3},$$
(11)
$${i}_{\mathrm{PP}}={i}_{1}+{i}_{2}-{i}_{3}-{i}_{4}.$$