Patent ID: 7307285

Claim:
An optical semiconductor device, comprising: a first set of lead frames having a first set of element mounting beds; a second set of lead frames having a second set of element mounting beds, the second set of element mounting beds being arranged substantially on a same plane as the first set of element mounting beds; a third set of lead frames having a third set of element mounting beds, the third set of element mounting beds being arranged substantially on a same plane as the first and second set of element mounting beds; a light-emitting element mounted on one of the first set of element mounting beds and having a pair of electrodes electrically connected to the first set of lead frames and a MOSFET pellet mounted on the second set of lead frames and the third set of lead frames; a light-receiving element supported by the MOSFET pellet and configured to receive a light emitted from the light-emitting element; and a dummy pellet mounted on the third set of lead frames.