| 摘要 |
<p>The present invention is a combined surface emitting semiconductor laser (18) and photodetector (30, 32) in a single housing with the photodetector positioned to detect light emitted from the surface emitting laser (18) and reflected off of a medium. The surface emitting laser (18) is mounted on the top surface of a chip (22) which includes at least one set of two photodetectors (30, 32) for detecting a reflected beam. At least two photodetectors (30, 32) are used so that spacial variations in the reflected beam can be detected for focusing and tracking when the device is used in an optical head. Photodetectors (30, 32) are arranged to intersect a diffracted beam from a hologram lens used in an optical head. A rear emission photodetector (28) for monitoring the power of the surface emitting laser (18) is positioned so that it will not receive diffracted light which will interfere with its operation.</p> |
