Optical components for very short reach applications at 40 Gb/s and beyond

Abstract

Just as the density of transistors on a silicon chip about doubles with each new generation, processor bandwidth also about doubles. Consequently the speed of input-output (I/O) devices must grow and today we find processor I/O speed approaching or slightly surpassing 10 Gb/s (G) per channel for 100G Ethernet server applications. Similarly Storage Area Networks are supported by Fibre Channel FC16G transceivers operating at the newly standardized serial signaling rate of 14 Gbaud. Further upgrades will require within only a few years links at 25, 28 and 40 Gbaud, speeds that are barely feasible with copper cabling, even for very short reach distances. Thus the role of optical interconnects will increase dramatically as the data transfer rates increase. Furthermore an increased bandwidth demand necessitates an equal or greater demand for low cost and highly power efficient micro-laser and -detector components along with their associated driver and transimpedance amplifier (TIA) integrated circuits (ICs). We summarize our recent achievements in vertical cavity surface emitting lasers (VCSELs) and PIN photodetectors suitable for very short reach multimode fiber links that enable bit rates up to and beyond 40 Gb/s. We address achievements in current modulated VCSELs, electrooptically modulated VCSELs, top illuminated PIN photodiodes, TIA and driver ICs, and packaging solutions.