Enhancing the Kramers-Kronig receiver via dispersion-based spatial diversity

We report a scheme for reconstructing the complex envelope of an optical signal from two decorrelated measurements of its intensity. The decorrelation is achieved by splitting the received optical signal into two copies, and by dispersing one of the copies prior to photo detection. The reconstructed complex-valued signal is obtained by means of an iterative algorithm that requires only a few tens of iterations. The starting point of the search procedure is produced by Kramers-Kronig (KK) reconstruction. With this procedure, the continuous-wave tone that accompanies the received signal is reduced by 5 dB to 6 dB compared to the requirement of a KK receiver alone.