High-frequency circuit design for 25 Gb/s×4 optical transceiver

A 25-Gb/s optical transceiver module has been developed for backplanes. An optical transceiver for backplanes is necessary to downsize current modules while reducing power consumption and increasing speed up to 25 Gb/s. We employed many approaches to achieve this by reducing crosstalk noise, by enhancing power integrity, and by using CMOS-based analog FE and on-chip termination and optical waveform optimization. The fully integrated transceiver IC was fabricated with the 65-nm CMOS process and the package was small, being 9 × 14 mm in size. We measured the output signal of the transceiver and obtained good eye-openings at 25 Gb/s.