Transverse phase-matched second-harmonic generation from counterpropagating beams for characterising ultrashort pulses

In this paper, a transverse quasi-phase-matched parametric upconversion is employed to realise a compact ultra-broadband correlator for characterisation of ultrashort pulses, thus bringing together the advantages of parametric processes in solid-state materials and the simplicity of the TPF method. Cross-correlations with reference pulses of known properties can be used in order to gain more information about the signal pulse. The technique can be well integrated with standard fiber components to result in a simple compact device for measurement of short pulses in telecom systems.