A semiconductor package includes a die, through insulator vias, an encapsulant, and a pair of metallization layers. The through insulator vias are disposed beside the die. The encapsulant wraps the die and the through insulator vias. The pair of metallization layers is disposed on opposite sides of the encapsulant. One end of each through insulator via contacts one of the metallization layers and the other end of each through insulator via contacts the other metallization layer. The through insulator vias form at least one photonic crystal structure. A pair of the through insulator vias is separated along a first direction by a channel filled by the encapsulant. A width of the channel along the first direction is larger than a pitch of the photonic crystal structure along the first direction.