MLSE-assisted decision feedback equalizer for error-propagation suppression in high-speed IM-DD transmission systems

We propose a trellis-compressed maximum likelihood sequence estimation (TC-MLSE)-assisted sliding-block decision feedback equalizer (DFE) to suppress the error propagation resulting from the DFE in high-speed systems. We use an out-of- range detector to detect the end of burst errors from the DFE and activate the optional TC-MLSE to correct burst errors. We conduct experiments to transmit a 201-Gbit/s PAM-8 signal. The results show that the proposed method achieves a bit error rate of 3.65 x 10-3, -3 , which is close to that of MLSE. The optional MLSE is only activated when needed and processes 11.4% of the total symbols. Moreover, the proposed method compresses the maximum length of burst errors from 19 to 5.