Spectral phase correlation of coded femtosecond pulses by second-harmonic generation in thick nonlinear crystals

We demonstrate a novel all-optical scheme for measuring the correlation of spectrally phase-coded ultrashort optical waveforms that uses second-harmon ic generation (SHG) in long, periodically poled lithium niobate crystals. T he SHG yield can be controlled over a range of similar to 30 dB, depending on the correlation of the applied phase codes. Such a spectral phase correl ator has applications for ultrashort-pulse optical code-division multiple-a ccess networking and could serve as a nonlinear optical but classical analo g for certain schemes for coherent quantum control of multiphoton processes . (C) 2000 Optical Society of America.