Novel monolithic optical receivers in 0.8-μm standard MOS technology with non-return-to-zero data rates in excess of 531 Mbit/s at 850 nm are introduced. At 638 nm the data rates are above 622 Mbit/s. The innovative integrated double and pin photodiodes allowing this high speed without any modification in a CMOS process are described, and results for their quantum efficiency and for their transient response are presented. Furthermore, the improvement of the sensitivity of the photodiodes and of the optoelectronic integrated circuits (OEICs) by an antireflection coating is discussed. The circuit topology of several OEICs is described. A transimpedance input stage with an active MOS feedback resistor is implemented. Analytical calculations for the bandwidth and for the overall transimpedance of several amplifiers as well as measured results are presented. Finally, an OEIC in a 1.0-μm CMOS technology with a polysilicon resistor instead of a MOS feedback resistor with a data rate of 1 Gbit/s for 638 nm is shown. The sensitivity of this OEIC is improved by at least 9 dBm over that of published OEICs.