For example, a surface emitting semiconductor laser and a driver IC are arranged
three-dimensionally to put a submounting substrate between them, and LSIs such
as a CPU, etc. are mounted on the driver IC. The surface emitting semiconductor
laser is formed of the epitaxial lift-off (ELO) process and has a thickness of
about 10 m. A through hole is provided to all the submounting substrate,
the surface emitting semiconductor laser, the driver IC, and the LSIs. These parts
are connected electrically mutually via conductor in the through hole.
