256-channel bidirectional optical interconnect using VCSELs and photodiodes on CMOS

Two-dimensional parallel optical interconnects (2-D-POIs) are capable of providing large connectivity between elements in computing and switching systems. Using this technology we have demonstrated a bidirectional optical interconnect between two printed circuit boards containing optoelectronic (OE) very large scale integration (VLSI) circuits. The OE-VLSI circuits were constructed using vertical cavity surface emitting lasers (VCSELs) and photodiodes (PDs) flip-chip bump-bonded to a 0.35-mum complementary metal-oxide-semiconductor (CMOS) chip. The CMOS was comprised of 256 laser driver circuits, 256 receiver circuits, and the corresponding buffering and control circuits required to operate the large transceiver array. This is the first system, to our knowledge, to send bidirectional data optically between OE-VLSI chips that have both VCSELs and photodiodes cointegrated on the same substrate.