Magneto-optic readout using a polarization-preserving optical fiber

Apparatus for reading out information magneto-optically recorded in a magnetic layer comprises a single, polarization-preserving optical fiber for transmitting plane-polarized readout radiation from a source to the recording layer, as well as for transmitting such radiation, upon being reflected by the recording layer, toward a pair of photodetectors for the differential detection of the Kerr rotation angles (+/- THETA k) produced by the up/down orientation of the vertically oriented magnetic domain in the recording layer. Optical feedback of the reflected readout radiation to the readout source is minimized by the provision of a pair of polarization beam-splitters having a 45 degree magneto-optic polarization-rotator (e.g. a Faraday rotator) positioned therebetween. The polarization beam-splitters and retardation plate are positioned in the optical path between the readout source and the optical fiber.