| 摘要 |
PURPOSE:To disperse light to first, second photosensers in the proportion of about 50% respectively by diffracting return diffracted beams in the prescribed direction to a polarization direction of a light beam from a light emitting element. CONSTITUTION:A grating space of a hologram 8 is reduced, and the incident angle of the return diffracted beams 14 to a polarizing separation film 15 is enlarged. Further, when the diffractive efficiency of a P polarization is defined etaP, and the diffractive efficiency of an S polarization etaS, a semiconductor laser chip 2, a reflection prism 4 and the hologram 8 are constituted so that the return diffracted beams 14 from an optical disk 11 is diffracted in the direction of an angle (theta) given by theta=tan<-1>(etaP/etaS) to the polarization direction of the beam from the light emitting element, and the beams are dispersed to the first photosenser 22 and the second photosenser 29 in the proportion of 50% respectively by the polarizing separation film 15. By such a manner, an excellent RF signal in which the same phase noise component except a magneto-optical signal is eliminated by the differential width of the first, second photosensers 22, 29 is provided. |
