An optical pickup apparatus used in an optical data recording/reproducing
apparatus for reading/reproducing data on an optical recording medium,
including a light source, a diffracting device configured to transmit a
light beam and to diffract a light beam reflected from the optical
recording medium, an optical device having a reflecting portion and a
transmitting portion configured to reflect one part of the light beam
emitted from the light source and to transmit another part of the light
beam to the optical recording medium and from the optical recording
medium, and a photodetecting device to detect the light beam from the
optical recording medium for signal light detection, and the light beam
reflected by the reflecting portion of the optical device for monitor
light detection of the light source.
