Optical interconnects for backplane and chip-to-chip photonics

The growth in computing power has placed increasing demands on low cost technologies for the transmission of large bandwidths over short distances using highly compact forms. As a result, in recent years a diverse range of photonic technologies have been developed not only to allow high speed point-to-point links, but also to enable the simple creation of networks within computing infrastructure, and indeed to allow an element of reconfiguration. In addition, related work has sought to make possible such functions directly on chip using new silicon based technologies. Following a general review of the field, this lecture will illustrate new cost effective optical technologies, developed at Dow Corning, which can be formed directly on printed circuit boards using materials that withstand solder overflow. The technology has the potential of delivering both board-to-board and chip-to-chip communications. For typical required lengths, polymer waveguides can be formed which are essentially bit rate transparent with high crosstalk performance. With readily available parallel optics, this allows a high capacity (of Terabit order) backplane performance. Recent results show efficient high-speed data transmission at 10 Gbps individual channel rates with low loss and excellent crosstalk performance. The lecture will conclude by reporting how we are exploring the potential extension of this technology for use in high-speed on-board optical networks.