Fiber-coupled balanced optical cross-correlator using PPKTP waveguides

We present a fiber-coupled balanced optical cross-correlator using waveguides in periodically-poled KTiOPO(4) (PPKTP). The normalized conversion efficiency of the waveguide device is measured to be η(0) = 1.02% / [W · cm(2)], which agrees well with theory and simulation. This result represents an expected improvement of a factor of 20 over previous bulk-optic devices. The sensitivity of the cross-correlator is characterized and shown to be comparable to the free-space bulk-optic version, with the potential for significant performance enhancements in the future.