A fully integrated multicolor photoreceiver

A fully integrated multicolor photoreceiver is presented, which combines a triple junction photodetector, three transimpedance amplifiers and three output drivers in a single chip. Gain and offset can be adjusted individually for each path. The fiber (glass fiber or POF) can be directly coupled onto the light sensitive area of the integrated receiver. The usable wavelength range is from 400 nm to 900 nm. The triple junction photodetector is designed based on the effect that light with longer wavelength can penetrate deeper into silicon than light with shorter wavelength. The three vertically stacked photodiodes can accurately and simultaneously convert light with different colors into different currents. The single chip photoreceiver is fabricated in standard 0.6 μm CMOS technology using an epi-wafer without any process modifications. Thus it can be realized cheap and with minimal packaging effort. In addition, the presented device can pave the way for a single visible WDM receiver - a solution optimal for high speed POF transmission systems. Based on the simulation results, we find that the designed photoreceiver can meet requirements of both color detections and a relatively high transmission rate up to 200 Mbps per color.