Patent ID: 7561762

Claim:
A semiconductor device having: a semiconductor element; a planar optical element; a main substrate where electric wiring connected to said semiconductor element and to said planar optical element is formed, and where an optical transmission medium which transfers light inputted into said planar optical element and/or light outputted from said planar optical element is fixed; a small substrate on one end of which is mounted said planar optical element, and another end of which is electrically connected to said main substrate and is fixed to said main substrate; and a fixing mechanism which fixes one end of said small substrate, where said planar optical element is mounted, to said main substrate so that an input-output surface of said planar optical element faces an optical input-output section of said optical transmission medium, wherein said small substrate has a flexible section, which is easily deformable in comparison with other portions of said main substrate and said small substrate, the flexible section disposed at least at a partial region between the end where said planar optical element is mounted and the end electrically connected to said main substrate, wherein at least a portion of the flexible section is bent in a direction away from printed wiring board to form a convex shape, wherein the portion of the flexible section that forms the convex shape is not fixed to printed wiring board.