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Characterization of a novel focusing/tracking technique with increased feedthrough immunity for optical-disk
Applied Optics
|September 22, 2010
Summary
This study introduces a double-astigmatic optical servo method to reduce pattern noise and optical servo crosstalk. The technique effectively suppresses feedthrough in focusing and tracking systems.
Area of Science:
- Optical Engineering
- Servo Systems
- Signal Processing
Background:
- Astigmatic-focusing/push-pull tracking-error detection is a sensitive optical servo technique.
- Undesired diffraction effects, termed pattern noise or optical servo crosstalk, occur due to aberrations and track crossings.
Purpose of the Study:
- To present a differential variant of the astigmatic technique to reduce pattern noise.
- To demonstrate the effectiveness of the double-astigmatic method in suppressing feedthrough.
Main Methods:
- Combining two astigmatic lenses and their detectors to create a differential astigmatic method.
- Utilizing numerical modeling and experimental data to validate the technique.
Main Results:
- The double-astigmatic method significantly reduces pattern noise caused by spurious astigmatism.
- Experimental data confirms the effectiveness of the technique in feedthrough suppression.
Conclusions:
- The double-astigmatic optical servo technique offers an effective solution for reducing pattern noise and optical servo crosstalk.
- This method enhances the reliability of focusing and tracking systems in optical disk drives.
