Optical integrated device for magneto-optical reproducing head

An optical integrated device for a magneto-optical reproducing head, comprising:

• a substrate;
• a first wave guide for guiding a light beam for irradiating a magneto-optical recording medium and a signal light beam reflected by the medium;
• a first TE-TM mode splitter for splitting said first wave guide into two wave guides;
• a second wave guide coupled to said first wave guide through said first splitter for guiding the light beam for irradiating the magneto-optical recording medium to said first wave guide;
• a third wave guide coupled to said first wave guide through said first splitter for guiding said signal light beam from said first wave guide;
• polarization plane rotation means arranged in a course of said third wave guide for rotating a polarization plane of said signal light beam;
• a second TE-Tm mode splitter for splitting said third wave guide into two wave guides;
• a fourth wave guide and a fifth wave guide coupled to said third wave guide through said second splitter for guiding detection light beams split by said second splitter;
• said five wave guides and said two mode splitters being formed on said substrate;
• wherein said first TE-Tm mode splitter guides all of a TM mode component and some of a TE mode component of the signal light beam reflected from the recording medium into said third wave guide.