Wavelength-Shift-Free 3R Regenerator for 40-Gb/s RZ System by Optical Parametric Amplification in Fiber

We demonstrate wavelength-shift-free 3R-regenerator for 40-Gb/s optical return-to-zero (RZ) system by optical parametric amplification (OPA) with a clock-modulated pump in highly nonlinear fiber. The power penalty is improved by 2.6 dB, and the signal power is amplified by 7 dB