Complexity Analysis of the Kramers–Kronig Receiver

We propose a low-complexity digital implementation of the Kramers-Kronig receiver and analyze its performance and complexity. In simulations and experiments, we find that a relatively small number of filter taps is sufficient to achieve a reasonably high accuracy for the phase retrieval and for the reconstruction of the complex field. We show that the Kramers-Kronig receiver performance strongly depends on details of the system design. Unnecessarily broad optical filters decrease the reception quality, because additional noise makes the violation of the minimum-phase condition more likely. Narrow optical filters, however, impose high local oscillator laser stability and reduce the flexibility of this kind of receiver architecture. Further, we demonstrate Kramers-Kronig reception of 16 QAM signals at a net data rate of 267 Gbit/s after transmission over 300 km of standard single-mode fiber. We compare the performance with a conventional intradyne receiver. In a back-to-back setting, we increase the net data rate to 300 Gbit/s.