Optical pickup employing a vertical cavity surface-emitting laser diode

摘要

An optical pickup is provided which detects information contained in an optical disk. The optical disk includes a light source, a hologram device, an objective lens, a photodetector, and a single chip. The light source is formed of a first vertical cavity surface-emitting laser (VCSEL) diode and emits a light beam. The hologram device converts the light beam emitted from said light source into a polarized parallel light beam and diffracts a reflected parallel light beam reflected from said optical disk to produce a diffracted beam. The objective lens focuses the polarized parallel light beam on said optical disk and converts a corresponding reflected beam into the parallel reflected beam. The photodetector is formed of a second VCSEL diode and detects various characteristics of the diffracted beam. Finally, the light source and the photodetector are integrated on the chip. As a result of the configuration above, the light source emits a laser beam which has a small astigmatism and does not lose its intensity as it propagates through the optical head.