Waveguide-based single-shot temporal cross-correlator
  We describe a novel technique for performing a single-shot optical cross-correlation in nanowaveguides. Our scheme is based on four-wave mixing between two orthogonally polarized input signals propagating with different velocities due to polarization mode dispersion. The cross-correlation is determined by measuring the spectrum of the idler wave generated by the four-wave mixing process. 
Moti Fridman, Yoshitomo Okawachi, Stephane Clemmen, Michael Menard,   Michal Lipson, and Alexander L. Gaeta
physics.optics