a housing;

an optical communication module accommodated in the housing, wherein the optical communication module comprises a substrate, a first optical communication component and a second optical communication component, and the first optical communication component and the second optical communication component are provided at opposite top and bottom surfaces of the substrate, respectively; and

a heat dissipation module comprising a first heat conductive component and a second heat conductive component disposed on and in physical contact with the substrate, wherein the first heat conductive component is spatially spaced apart from the second heat conductive component, the first optical communication component is supported on and in thermal contact with the first heat conductive component, the second optical communication component is mounted on the substrate, and the second optical communication component is in thermal contact with the second heat conductive component through the substrate.