Complexity Analysis of the Kramers–Kronig Receiver

Abstract

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.