Optical communication apparatus comprises: a first IC assembly disposed at a first PCB and comprising: a first IC package electrically coupled to circuits of the first PCB and having an opening in a bottom layer thereof; a first array of optical elements disposed in and electrically coupled to the first IC package and aligned with the bottom layer opening; and a tube of optical fibers disposed in the bottom layer opening with one end aligned under the first array and another end protruding out from the bottom layer of the first package and extending through a hole in the first PCB; a second IC assembly disposed at a second PCB, arranged in parallel with the first PCB, and comprising: a second IC package electrically coupled to circuits of the second PCB and having an opening in a top layer thereof; and a second array of optical elements disposed at the second IC package and electrically coupled thereto through the top layer opening; and wherein the second array being optically aligned with the optical fiber tube of the first IC package to accommodate optical communication between the arrays through the optical fibers of the tube. Various other embodiments of the apparatus are also disclosed.