title: Noise-figure limit of fiber-optical parametric amplifiers and wavelength converters: experimental investigation.
abstract: Recent theoretical work predicts that the quantum-limited noise figure of a x(3)-based fiber-optical parametric amplifier operating as a phase-insensitive in-line amplifier or as a wavelength converter exceeds the standard 3-dB limit at high gain. The degradation of the noise figure is caused by the excess noise added by the unavoidable Raman gain and loss occurring at the signal and the converted wavelengths. We present detailed experimental evidence in support of this theory through measurements of the gain and noise-figure spectra for phase-insensitive parametric amplification and wavelength conversion in a continuous-wave amplifier made from 4.4 km of dispersion-shifted fiber. The theory is also extended to include the effect of distributed linear loss on the noise figure of such a long-length parametric amplifier and wavelength converter.
authors.affiliation: Center for Photonic Communication and Computing, Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208-3118, USA.
authors.forename: Renyong
authors.initials: R
authors.lastname: Tang
authors.forename: Paul L
authors.initials: PL
authors.lastname: Voss
authors.forename: Jacob
authors.initials: J
authors.lastname: Lasri
authors.forename: Preetpaul
authors.initials: P
authors.lastname: Devgan
authors.forename: Prem
authors.initials: P
authors.lastname: Kumar