We describe our R & D on optoelectronic packaging technologies such as the optical backplane utilizing 300 pieces of the high index contrast fine multimode fibers and the low-cost and high-density OE-conversion parallel link modules operating at 10 Gbps /ch for less than 1 m regime applications. Combination of the developed backplane and the modules implies potential of 3 Tbps aggregate throughputs at the board-to-board level optical interconnections. We also introduce novel component technologies for low-cost and high-density optical coupling between optical devices. These technologies include the monolithic two wavelengths twin VCSELs and easy self-alignment coupling technology capable of alleviating difficulties for optics penetration inside the box.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.