Ultrafast All-Optical Differentiators Based on Fiber Gratings

We review our recent advances on the experimental realization and application of ultrafast all-optical temporal differentiators. Differentiation has been obtained via all-fiber filtering based on a simple diffraction grating- assisted mode coupler (uniform long-period fiber grating) that performs full energy conversion at the optical carrier frequency. Due to its high bandwidth, this device allows processing of arbitrary optical signals with sub- picosecond temporal features (down to 180-fs with the specific realizations shown here). Ultrafast all-optical differentiators are of interest for a wide range of applications, including ultrahigh-bit-rate optical communications, ultrafast optical computing and information processing, optical pulse shaping and metrology of ultrafast optical events.