An 11.1 Gbps Analog PRML Receiver for Electronic Dispersion Compensation of Fiber Optic Communications

A dispersion tolerant receiver for fiber-optic links, in 0.18 μm SiGe BiCMOS, implements a Class-2 partial response maximum likelihood (PRML) equalization entirely in the analog domain. Post-FEC error free operation is achieved with data received from over 400 Km of uncompensated single mode fiber (SMF). The 4.5 W ASIC operates at up to 11.1 Gb/s and includes a variable gain amplifier (VGA) with automatic gain control (AGC), a 1.5-3.5 GHz programmable continuous-time filter (CTF), a 5-tap sampled-time finite-impulse response (FIR) filter, a decision directed timing recovery, and a 4-state analog Viterbi detector implementation. The receiver is compliant with XFI jitter specifications for Telecom applications (SONET OC-192 and G.709 “OTU-2”).