Optical Communication in CMOS - Bringing new opportunities to an established platform

This work discusses the design of 1310/1550 nm fully integrated optical receivers in bulk CMOS, suitable for single-mode fiber communication. The key enabler for detection of these sub-band gap wavelengths is internal photoemission in Schottky photodiodes. With standard bulk CMOS processes not conceived for these type of devices, the first step toward full receivers is adequate modeling. As these devices have modest responsivities, care must be taken in minimizing the input-referred noise current of the receiver front-end. To this end, SNR optimization of receiver front-ends without and with equalization is thoroughly discussed. Making use of this design flow, three fully integrated receiver prototypes with Schottky photodiodes suitable for 1310/1550 nm light are presented in depth, which demonstrate Gb/s performance.