Light receiving and emitting integrated device, optical pickup provided therewith, and optical disk apparatus

An optical pickup apparatus that records information on an optical recording medium and/or reproduces information recorded on an optical recording medium, the optical pickup apparatus comprising:

• a light receiving and emitting integrated device comprising:
• a light source for emitting light;
• a light branching element configured to branch the light emitted from the light source into at least three lights;
• a light dividing element being divided into four or more regions and configured to divide the light emitted from the light source and reflected by the optical recording medium into four or more lights;
• and
• a light receiving element, having four or more light receiving segments, configured to receive and output light divided by the light dividing element,
• wherein four or more lights obtained from the light dividing element dividing a first light from the at least three lights branched by the light branching element are received and detected by the four or more light receiving segments, and a focus servo signal is obtained by a knife edge method using detection outputs from the four or more light receiving segments,
• wherein the light source emits lights of different wavelengths and at least two first lights generated by branching each of at least two lights of different wavelengths emitted from the light source are each divided into four or more lights by the light dividing element and the four or more divided lights corresponding to each of the at least two first lights are received and detected by the four or more light receiving segments;
• and
• first to fourth output circuits configured to output as four signals at least eight or more detection outputs corresponding to the four or more lights of each of the at least two first lights which are divided at the same dividing region of the light dividing element and outputted from the four or more light receiving segments by connecting together detection circuits connected to the light receiving segments that receive and detect each of the at least two first lights.