Patent ID: 8249402

Claim:
A multilayer printed circuit board comprising: a plurality of optical circuits comprising a first optical circuit layer and a second optical circuit layer; an insulating layer comprising an adhesive insulating material and having a first surface and a second surface on an opposite side of the first surface, the insulating layer adhering the first optical circuit layer on the first surface and the second optical circuit layer on the second surface; a first layered structure formed over the first optical circuit on an opposite side of the insulating layer and comprising at least one substrate and a plurality of conductor circuits; a second layered structure formed over the second optical circuit on an opposite side of the insulating layer and comprising at least one substrate and a plurality of conductor circuits; and an optical signal transmitting region formed through the first layered structure and optically coupled to the first optical circuit layer, wherein at least one of the first and second layered structures further comprises a transparent solder resist layer formed as an outermost layer, and the transparent solder resist layer is formed over the optical signal transmitting region.