Complex signal field retrieval based on improved Kramers-Kronig coherent receiver without digital upsampling

Kramers-Kronig (KK) receivers have superior performance compared to the other single-photodiode-per-polarization simplified coherent receivers (SCRs) based on digital linearization techniques. But KK detection necessitates digital upsampling to avoid the frequency aliasing distortions caused by logarithm operation induced bandwidth increasement (LIBI). In this paper we proposed an improved KK (IKK) detection method utilizing a large virtual carrier to mitigate the LIBI. Compared to conventional KK detection, IKK detection exhibits better performance in Nyquist sampling rate. Numerical simulations and experiment are carried out to validate the conclusions and the superior performance of IKK receivers.