| 摘要 |
An optical pickup of an optical disk storage device with laser diodes which have two different wavelengths in one package type is provided to perform a exacter tracking error checking function by eliminating unnecessary sub beams when the pickup uses a DPP(Differential Push Pull) method to check a tracking error, therefore exacter data is written and read. A laser diode package unit(901) emits light sources having two different kinds of wavelengths. At least more than one of half-wave polarizers(902,905) changes polarized properties of one of the light sources. At least more than one of polarizer selection gratings(903,904) generates a phase difference of the light source whose polarized properties are changed, and generates a tracking error signal.
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