A semiconductor package includes a redistribution structure, a supporting layer, a semiconductor device, and a transition waveguide structure. The redistribution structure includes a plurality of connectors. The supporting layer is formed over the redistribution structure and disposed beside and between the plurality of connectors. The semiconductor device is disposed on the supporting layer and bonded to the plurality of connectors, wherein the semiconductor device includes a device waveguide. The transition waveguide structure is disposed on the supporting layer adjacent to the semiconductor device, wherein the transition waveguide structure is optically coupled to the device waveguide.