2018 Volume 7 Issue 2 Pages 37-42
We propose a novel pre-equalizer for multi-level IQ-modulation signals. The pre-equalizer is composed of multiple binary analog finite impulse response (FIR) filters which can realize smaller integrated-circuit (IC) chip size. In the proposed design scheme, required complex-number operations are implemented by a butterfly construction of real-number FIR filters. The analog FIR filters were designed using 28 nm fully depleted silicon on insulator (FD-SOI) based complementary metal-oxide-semiconductor (CMOS) circuits. The performance was investigated using numerical simulation of a 40-Gb/s 16-ary quadrature amplitude modulation (16-QAM) standard single-mode fiber (SSMF) transmission system. The simulated CMOS circuits successfully compensated the 16-QAM signals distorted by chromatic dispersion. The error vector magnitude (EVM) of the transmitted 16-QAM signals was improved from 27% to 12%.