16QAM spectral efficiency frequency division multiplexing transmission with Tomlinson-Harashima precoding for intensity modulation and direct detection optical links

In the spectral efficient frequency division multiplexing (SEFDM) system, in order to minimize mutual interference between subcarriers, a detector should be introduced at the receiver to handle the interference, but increases the complexity of system. In this paper, we propose a simplified precoding algorithm at transmitter instead of receiver, which can first implement higher 16QAM SEFDM transmission over standard single mode fiber (SSMF). The technique is based on interference information from non-orthogonality between subcarriers and uses nonlinear matrix operations to improve system performance with low complexity. The numerical results show that the precoding scheme achieves SSMF transmission of intensity modulation and direct detection (IM/DD) 16QAM SEFDM system under the premise of achieving higher spectral efficiency, and obtains good bit error rate performance.