Abstract

Differential phase detection (DPD) utilizes the rotation of the total diffraction pattern that is collected in the exit pupil of an optical data storage system. By placing a quadrant cell detector in the exit pupil of the system, the DPD signal may be calculated as the phase difference that arises between the diagonal detector currents. Figure 1 is a schematic representing how the DPD signal is formed.

© 1998 Optical Society of America