An optical integration device includes a first circuit layer comprising a first surface adjacent a first diffractive layer, the first diffractive layer arranged on a side of the first circuit layer along a first direction, and a first connecting pad electrically connected with the first circuit layer through a first conductive member. The optical integration device includes a side surface extending along the first direction. The side surface defines a first concavity extending through the first diffractive layer along the first direction. The first connecting pad includes a first mounting member connected with the side surface, and a first convex member extending from the first mounting member and received in the first concavity. The first conductive member includes a first conductive part arranged between the side surface and the first mounting member, and a second conductive part arranged between the first surface and the first convex member.