All-optical two-dimensional serial-to-parallel pulse converter using an organic film with femtosecond optical response

In this study, we introduce a new concept of all-optical two-dimensional se rial-to-parallel pulse converters. Femtosecond optical pulses can be unders tood as thin plates of light traveling in space. When a femtosecond signal- pulse train and a single gate pulse were fed onto a material with a finite incident angle, each signal-pulse plate met the gate-pulse plate at differe nt locations in the material due to the time-of-flight effect. Meeting poin ts can be made two-dimensional by adding a partial time delay to the gate p ulse. By placing a nonlinear optical material at an appropriate position, t wo-dimensional serial-to-parallel conversion of a signal-pulse train can be achieved with a single gate pulse. We demonstrated the detection of parall el outputs from a 1-Tb/s optical-pulse train through the use of a BaB2O4 cr ystal. We also succeeded in demonstrating 1-Tb/s serial-to-parallel operati on through the use of a novel organic nonlinear optical material, squaryliu m-dye J-aggregate film, which exhibits ultrafast recovery of bleached absor ption.