Performance of Fractionally Spaced MLSE in OOK and PAM4 Bandwidth Limited Optical Systems

Abstract

We analyze the performance of fractionally spaced maximum likelihood sequence estimation (MLSE) equalizers in OOK and PAM4 optical systems using optical and electrical components with cut-off frequencies less than the baud rate. It has been demonstrated that signals suffering from optical and electrical impairments can be efficiently equalized in cheap direct-detection optical receivers using MLSE equalizers with one or two samples, depending on the extent of bandwidth limitations.

Keywords

• Maximum likelihood sequence estimation
• chromatic dispersion
• bandlimited systems
• direct detection
• digital receiver