| 摘要 |
PURPOSE:To eliminate the noises caused by the return light and to obtain a compact and light-weight magneto-optical head device by reflecting the linear polarized light received from a semiconductor laser by the light quantity higher than a specific ratio to obtain the rectangular reflected light and using this reflected light as the return light to the semiconductor laser. CONSTITUTION:An external resonance optical system 10 consists of a beam splitter 6 which reflects the incident parallel luminous flux 5 by the >=20% light quantity as the rectangular reflected light 5B and an external reflecting mirror 11. The outgoing linear polarized light 2 of a semiconductor laser 1 is turned into the parallel luminous flux 5. The flux 5 is partly (>=20%) reflected by the beam splitter 6 and turned into the rectangular reflected light 5B. The light 5B is reflected by the mirror 11 and fed back to the laser 1 as the return light 15A via a return optical path 15 consisting of the splitter 6, etc. Under such conditions, the laser 1 has the stable oscillation in a single mode. As a result, the back talk noises produced by the return light are eliminated. Thus it is possible to obtain a compact and light-weight magneto-optical magnetic head at the low cost without using a high frequency superposition circuit. |
