Patent ID: 7783143

Claim:
A semiconductor device having: a semiconductor element; a planar optical element; a main substrate 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 child substrate which is connected electrically to said main substrate and is fixed to said main substrate; a small substrate on one end of which is mounted said planar optical element, and another end of which is electrically connected to said child substrate and is fixed to said child 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 in at least a partial region between one end where said planar optical element is mounted and another end electrically connected to said child substrate.