Semiconductor laser device and optical pickup device

Abstract

Semiconductor laser device and optical pickup device. In this semiconductor laser device, a polarization hologram transmits an outgoing beam directed from a semiconductor laser chip to an optical disk as a forward beam without diffracting the beam, and diffracts a backward beam of the laser beam, which is a return beam of the forward beam that has been reflected by the optical disk, so that the backward beam is deflected from a direction directed toward the semiconductor laser chip part and further directed toward first, second photoreception parts. Therefore, optical loss on the forward way from the semiconductor laser chip to the optical disk can be reduced, and return light to the semiconductor laser chip can be suppressed, so that a high-power, high-sensitivity semiconductor laser device can be realized.

Description

(1) Technical field [0001] The present invention relates to a semiconductor laser device and an optical pickup device, for example, to a semiconductor laser device and an optical pickup device suitable for an optical disc device that optically records information on or from an information recording medium such as an optical disc. reproduce the information. (2) Background technology [0002] In order to make the optical pickup device smaller in size, thinner in thickness and higher in reliability, an optical pickup device equipped with a hologram element has appeared. FIG. 8 shows an example of a semiconductor laser device equipped with a hologram element to constitute an optical pickup device. [0003] In this semiconductor laser device, first, a laser beam 107 emitted from a semiconductor laser chip 101 is diffracted by a grating element 103 . Note that the semiconductor laser chip 101 is placed on the rod 106 and the grating element 103 is placed on the hologram element / ...

AI Technical Summary

Problems solved by technology

[0009] As a result, the ratio of the 0th-order diffracted beam in the hologram element 104 must be set to a higher value, but, in this case, the diffraction efficiency in the hologram element 104 on the backward path will inevitably become low, thereby The signal strength of the diffracted light beam diffracted toward the light receiver 102 will inevitably become lower

Also, since the hologram element 104 has a high ratio of the 0th order diffracted beam, the ratio of the backward beam from the disc to the laser chip 101 will also be high, causing noise as described above, which can cause difficulties in use

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