| Design of a 1-tap decision feedback equalizer (DFE) at 40-Gbps is investigated for polarization-mode dispersion (PMD) compensation of single-mode fibre. The DFE is fabricated in 0.18mum SiGe BiCMOS technology with a 160-GHz ft. In order to meet the high speed requirements, a look-ahead architecture is employed to decrease the propagation delay within the feedback path, while maintaining full functionality. Modifications to the architecture were made to ease the requirements on the clock distribution. Measurements show the DFE able to equalize a PMD emulating channel as well as a 20-ft SMA cable up to 10 Gbps with bit error checking. At 40 Gbps, the DFE compensated for a 9-ft SMA cable and functional verification was conducted by hand. The IC occupies an area of 1.5 mm2 and operates from a 3.3 V supply with 230 mA of current. To the author's knowledge, this is the first fully functional 40-Gbps DFE in any technology. |
