Researchers from the Aston-NSU International Centre for Photonics at the 吃瓜官网, Aston Institute of Photonic Technologies and the telecommunication company MPB Communications Inc. - S.K. Turitsyn, A.E. Bednyakova, M.P. Fedoruk, S.B. Papernyi and W. R. L. Clements, in Nature Photonics experimental and theoretical study of a new nonlinear effect in fiber optics - inverse four-wave mixing or self-parametric amplification.
It is 鈥渃ommon knowledge鈥� in fiber-optics that nonlinear effects such as four-wave mixing and self-phase modulation manifest themselves as a spectrum broadening when relatively high power CW signals propagate in optical telecommunication fibers. In the published paper, it was observed experimentally and confirmed through comprehensive numerical modeling that the spectral width of a CW signal produced by a Raman fiber laser can become substantially narrower after propagation in a normal dispersion fiber. Unusual behavior of light is the result of a nonlinear energy re-distribution from the tails of signal spectrum to the central region.
Moreover, the resulting spectral distribution does not change appreciably with propagation over long distance of normal dispersion fiber. This new effect may potentially be exploited in fibre lasers and optical telecommunications. In fiber lasers, nonlinear compression may lead to increased spectral brightness compared to systems using direct spectral filtering, avoiding additional losses inevitable with filters. In optical communications, spectrally stable nonlinear propagation regimes may lead to new techniques of mitigation of nonlinear transmission impairments that are a major challenge in modern high-capacity transmission systems.
