Abstract

As well-known, optical phase conjugation undoes optical signal distortions upon propagation in dispersive and nonlinear medium [1]. By generating the conjugate replica of a signal at the middle of fiber-optic transmission link, dispersive and nonlinear broadenings may be compensated for [2]. When applied to soliton systems, mid-span spectral inversion also removes other important transmission capacity-limiting effects such as pulse interactions [3]. Four-wave mixing in fibers may also be exploited for wavelength-shifting and time-demultiplexing of high-bit-rate signals. For efficient and broadband frequency conversion, pumping near the zero-dispersion wavelength of a dispersion-shifted fiber (DSF) is required [4,5]. As a result, the fiber group-velocity dispersion (GVD) has opposite signs at the signal and conjugate wavelengths. In the conjugation of ultrashort solitons, that is for DSF lengths equal or longer than the dispersion distance, the effect of finite GVD at the signal and conjugate wavelengths sets a fundamental limit to the conversion efficiency.

© 1998 Optical Society of America