| 摘要 |
PURPOSE:To make the head small in size and to increase its frequency change by approaching one end face of a semiconductor laser to a magneto-optic disk and inserting a wavelength plate made of a rutile inbetween. CONSTITUTION:A nonreflecting film 22 is applied to both end faces of a semiconductor laser chip 20 and rutile single crystal made thin wavelength plates (lambda/4 plates) 23, 24 are provided on the film. The light radiated from the semiconductor laser 20 is reciprocated in a path of lambda/4 plates 24 - magneto-optic disk 27 - lambda/4 plate 24 - semiconductor laser 20 to stimulate laser oscillation. In this case, the light 1 (figure in a round mark, omitted hereinafter) in the TM mode in the laser 20 is converted into a circularly polarized light 2 through the lambda/4 plate 24 and made incident in a disk 27, reflected (2) and becomes a circularly polarized light 3 in reverse rotation, and returned in the TE mode orthogonal to the initial linearly polarized light 1 through the lambda/4 plate 24. On the other hand, the linearly polarized light transmitted through the laser 20 changes in the order of 6 7 8. Beat signals of two modes are obtained by the Kerr rotation by the magnetized plane of the disk 27. |
