All-fiber distributed compression of weak pulses in the regime of negative group-velocity dispersion

The authors investigate the compression of a weak optical pulse at a wavelength in the anomalous dispersion regime by propagating it in a fiber together with an intense pulse whose wavelength lies in the region of positive group-velocity dispersion and is adjusted so that walkoff is minimized. Specifically, it is shown that a fiber can be used as a distributed compressor for a weak pulse at a wavelength from the negative dispersion regime when it is propagated with an intense pump pulse whose wavelength corresponds roughly to the opposite side of a dispersion curve. The authors presented an analytical approximation describing how the evolution of the compressed pulse envelope and chirp depends on the physical parameters involved in the process in the first stage of the compression