A monolithic GaAs-on-Si receiver front end for optical interconnect systems

The authors describe a monolithic technology for integrating GaAs with Si bipolar devices and demonstrate that such integration can provide improved system performance without degrading individual devices. The technology has been used to implement a 1-GHz GaAs/Si optical receiver with an equivalent input noise current density of less than 3 pA/√Hz for midband operation, and less than 4.5 pA/√Hz at 1 GHz. In this receiver an interdigitated GaAs metal-semiconductor-metal (MSM) photodetector is combined with a transimpedance preamplifier fabricated in silicon bipolar technology. The measured dark current of the GaAs/Si photodetector is 7 nA. The measured pulse response of an experimental integrated receiver is less than 550 ps FWHM. The integrated front end provides a wideband, low-noise optical receiver for use in local optical interconnections and demonstrates the successful application of integrated GaAs-on-Si technology to optoelectronics