8 Gb/s CMOS compatible monolithically integrated silicon optical receiver

Abstract

Several standards for high-speed optical data communications links (Gigabit Ethernet, OC-48, OC-192) include a local area network (LAN) version at 850 nm, where high-speed, low cost vertical-cavity-surface-emitting lasers (VCSEL) are readily available. There is an increasing demand for high-volume, low-cost optical receivers that operate at this wavelength. CMOS technologies have potential for very low-cost high volume optoelectronic components. Since silicon exhibits absorption at 850 nm, Si-based optical receivers are attractive for LAN applications. Several monolithic optical receivers in an unmodified CMOS fabrication process have been reported1−3 for bit rates up to 2.1 Gb/s. The low absorption coefficient 15 µm−1 of silicon at 850 nm makes it difficult to integrate a high efficiency and high-speed photodetector into the CMOS process flow and therefore a compromise between speed and sensitivity must be made. © 2002 Optical Society of America