An optical transmitter is equipped with a laser diode and a light detector
provided on a packaging base, in which the light detector has a
semiconductor substrate side arranged on a packaging base side, a
semiconductor junction plane, a side surface which is roughly orthogonal
to the semiconductor junction plane, and a facing surface which faces the
side surface, wherein the facing surface is partially or completely
inclined to reflect the output light from the laser diode incident from
the side surface to the semiconductor junction plane of the light
detector.
