Odd-Even Symbol Dispersion Pre-Compensation Technique Utilizing Interleaved Dual-FIR Filters in IM-DD Systems

An interleaved odd and even samples electrical dispersion pre-compensation (pre-EDC) scheme with low complexity is proposed to alleviate the severe distortions caused by frequency-selective fading due to chromatic dispersion (CD) in the intensity-modulation and direct-detection (IM-DD) optical transmission systems. This scheme utilizes training-based interleaved dual finite impulse response (FIR) filters for odd and even samples pre-compensation, respectively, referred to as training-based ID FIRs-pre-EDC. Additionally, a Tx and Rx side joint scheme is proposed to enhance the performance of the training-based ID FIRs-pre-EDC by implementing the efficient reduced state maximum likelihood sequence estimation (RS-MLSE) at the receiver side. Experimental validations in a C-band 56 Gbit/s PAM-4 80 km standard single-mode fiber (SSMF) transmission system show that the training-based ID FIRs-pre-EDC achieves over 0.95 dB receiver sensitivity improvement at the 7% hard-decision forward error correction (HD-FEC) threshold compared to traditional FIR-pre-EDC schemes. Employing the proposed joint scheme obtains ∼3 dB receiver sensitivity gain at the 7% HD-FEC threshold compared with only implementing training-based ID FIRs-pre-EDC at the transmitter side. These results indicate the potential and feasibility of the proposed schemes in optical interconnects.