Gerchberg-Saxton Based FIR Filter for Electronic Dispersion Compensation in IM/DD Transmission Part II: Experimental Demonstration and Analysis

In this article, the first experimental demonstration of a non-iterative electronic dispersion compensation (EDC) solution implemented at transmitter using finite impulse response (FIR) filter optimized with Gerchberg-Saxton (GS) algorithm, is presented, for intensity-modulation and direct-detection (IM/DD) systems. The theoretical framework preliminary simulations have been presented in Part I work. Here, performance compared between GS FIR iterative algorithm 56-Gb/s on-off keying (OOK) transmissions over 80-km single mode fiber (SMF) post feed-forward equalizer (FFE) combating residual inter-symbol interference. Furthermore, influence pulse shape (raised cosine or rectangular) modulation format (return-to-zero (RZ) non-return-to-zero (NRZ)) on measured bit error ratio (BER) investigated, while changing number taps, post-FFE samples-per-symbol. It shown that within range target digital extinction ratios (DERs) which original offers benefit, both analytical numerical methods calculating optimum outlined I, produce similar BER as predicted. Hence, former method extended, here, through non-recursive frequency formula, insight into action different shaping enables derivation explicit response. also rectangular RZ exploits full benefit filtering uniform spectrum, achieving < 3.8×10 −3 , 641-tap T /2-spaced pre-EDC 3-tap adaptive -spaced post-FFE.