A semiconductor package includes an interconnect structure having a first surface and a second surface opposite to the first surface, an insulating layer contacting the second surface of the interconnect structure wherein the insulating layer has a third surface facing the second surface of the interconnect structure and a fourth surface opposite to the third surface, at least one optical chip over the fourth surface of the insulating layer and electrically coupled to the interconnect structure, and a molding compound over the first surface of the interconnect structure.