High-Dynamic Range Wide-Band Integrated Receiver for Optical Transmission Using a Gain Switch at the Input

The front-end of optical transmission systems usually consists of a low-noise wide-band negative-feedback transimpedance or current-amplifier. The dynamic range of this type of amplifier can be extended considerably by using a low-noise current-switch at the input of the amplifier. This switch bypasses large in- put signals directly to the output. The design strategy of both the switch and the amplifier is presented. A complete receiver, having a dynamic range of 83dB in a bandwidth of 220MHz and consuming a supply current of 1.5mA, is realized in a 2.5GHz bipolar technology.